THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 

NATURAL  HISTORY  SURVEY 

5705 
ILL 

v7cop.4 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 

Vol.  VII  October,  1922  No.  4 


Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate  School  by 

the  University  or  Illinois  Press 


Copyright,  1923  by  the  University  or  Illinois 
Distributed  February  9, 1923 


A  CLASSIFICATION  OF  THE  LARVAE 
OF  THE  TENTHREDINOIDEA 


WITH  FOURTEEN  PLATES 


BY 

HACHIRO  YUASA 


Contributions  from  the 

Entomological  Laboratories  of  the  University  of  Illinois 

No.  69 


THESIS 

SUBMITTED   IN  PARTIAL    FULFILMENT  OF  THE  REQUIREMENTS   FOR  THE   DEGREE 

OF  DOCTOR  OF  PHILOSOPHY  IN  ENTOMOLOGY  IN  THE  GRADUATE 

SCHOOL  OF  THE  UNIVERSITY  OF  ILLINOIS 

1920 


TABLE  OF  CONTENTS 

I.    Introduction 7 

II.    Morphology 14 

III.    Taxonomy 35 

Superfamily  Tenthredinoidea 37 

Families  of  Tenthredinoidea 38 

Family  Xyelidae 39 

Family  Blasticotomidae 42 

Family  Tenthredinidae 42 

Subfamilies  of  Tenthredinidae 43 

Subfamily  Diprioninae 45 

Neodiprion  Rohwer 46 

Species  of  Neodiprion 47 

Monoctenus  Dahlbom 48 

Diprion  Schrank 49 

Subfamily  Emphytinae , 49 

Genera  of  Emphytinae 50 

Subfamily  Selandriinae 51 

Genera  of  Selandriinae 52 

Thrinax  Konow , 52 

Species  of  Thrinax 53 

Strongylogaster  Dahlbom 53 

Species  of  Strongylogaster 53 

Selandria  Leach 54 

Subfamily  Dolerinae 54 

Dolerus  Jurine 55 

Species  of  Dolerus 56 

Subfamily  Phyllotominae 57 

Tribe  Phyllotomini 57 

Genera  of  Phyllotomini 58 

Endelomyia  Ashmead 58 

Caliroa  Costa 58 

Species  of  Caliroa 59 

Tribe  Phlebatrophini 59 

Phlebatrophia  MacGillivray 60 

Subfamily  Tenthredininae 60 

Genera  of  Tenthredininae 61 

Macrophya  Dahlbom 62 

Species  of  Macrophya 63 

Subfamily  Cimbicinae 64 

Genera  of  Cimbicinae 65 

Cimbex  Olivier 65 

Trichiosoma  Leach 65 

Abia  Leach 65 

Species  of  Abia 66 

Subfamily  Hoplocampinae 66 

Genera  of  Hoplocampinae 67 

Hemichroa  Stephens 67 

Marlattia  Ashmead 68 

Caulocampus  Rohwer 68 

Subfamily  Dineurinae 69 

Subfamily  Cladiinae : 70 

Genera  of  Cladiinae 71 

Trichiocampus  Hartig 71 

Species  of  Trichiocampus 72 

Priophorus  Dahlbom 73 

Species  of  Priophorus 73 

Cladius  Rossi 74 

Subfamily  Nematinae 74 

Genera  of  Nematinae 75 


Diphadnus  Hartig 76 

Pnstiphora  Latreille 77 

Species  of  Pristiphora 77 

Micronematus  Konow 79 

Lygaeonematus  Konow 81 

Pachynematus  Konow 81 

Species  of  Pachynematus 82 

Nematus  Panzer 82 

Species  of  Nematus 83 

Croesus  Leach 83 

Amauronematus  Konow 84 

Species  of  Amauronematus 84 

Pteronidea  Rohwer 85 

Species  of  Pteronidea 85 

Pontania  Costa 88 

Species  of  Pontania 88 

Subfamily  Blennocampinae 91 

Genera  of  Blennocampinae 92 

Tomostethus  Konow 92 

Blennocampa  Hartig 93 

Erythraspiaes  Ashmead 94 

Monophadnus  Hartig 94 

Hypergyricus  MacGillivray 94 

Species  of  Hypergyricus 94 

Monophadnoides  Ashmead 95 

Isodyctium  Ashmead 95 

Subfamily  Fenusinae 96 

Genera  of  Fenusinae 96 

Kaliofenusa  MacGillivray 97 

Fenusa  Leach 97 

Subfamily  Scolioneurinae 98 

Metallus  Forbes ;. ...  98 

Species  of  Metallus 99 

Subfamily  Hylotominae 99 

Hylotoma  Latreille 100 

Species  of  Hylotoma 100 

Subfamily  Schizocerinae 101 

Schizocerus  Lepeletier 102 

Subfamily  Acordulecerinae 103 

Acordulecera  Say 103 

Species  of  Acordulecera 103 

Family  Pamphiliidae 104 

Species  of  Pamphiliidae 105 

Family  Cephidae 108 

Genera  of  Cephidae ...;•.. 109 

Janus  Stephens 110 

Species  of  Janus 110 

Adirus  Konow 110 

Trachelus  Jurine Ill 

Cephus  Latreille ...  Ill 

Species  of  Cephus Ill 

Hartigia  Schiodte 112 

Family  Xiphydriidae 112 

Xiphydria  Fallen 113 

Family  Siricidae . 114 

Tremex  Jurine 115 

Family  Megalodontidae 116 

Family  Oryssidae 117 

Oryssus  Latreille 118 

IV.  Phylogeny 120 

V.  Summary 133 

VI.  Bibliography 135 

VII.  Explanation  of  Plates 141 

VIII.  Index 169 


325J  LARVAE  OF  THE  TENTHREDJNOIDEA—YUASA 


I.  INTRODUCTION 

That  the  cardinal  principle  of  modern  taxonomy  is  based  on  the  funda- 
mental facts  of  evolution  and  that  the  essential  problem  of  classification 
is  the  phylogenetic  relationship  of  organisms  need  no  argument.  In  order 
to  ascertain  genetic  affinities,  it  is  not  sufficient  to  investigate  the  morpho- 
logical characters  alone,  but  all  other  attributes,  physiological  and  biolog- 
ical, must  be  considered.  It  is  also  evident  that  the  immature  stages  of 
organisms  should  receive  as  thoro  consideration  as  the  adult  if  taxonomy 
of  insects  is  to  attain  that  degree  of  comparative  perfection  obtained  in  the 
classification  of  other  organisms. 

Systematic  entomologists,  dealing  as  they  do  with  animals  of  such 
diversity  and  complexity  morphologically  and  biologically,  have  from 
early  times  recognized,  at  least  to  some  extent,  the  taxonomic  significance 
and  value  of  the  developmental  stages  of  insects,  but  the  practical  difficul- 
ties in  obtaining  necessary  materials,  accurately  determined  and  adequate 
in  quantity  and  range,  have  made  progress  in  this  phase  of  insect  taxonomy 
very  tardy.  A  good  start,  however,  has  been  made  by  recent  workers  as 
was  pointed  out  by  Brues  (1919),  and  their  results  vindicate  both  the 
possibilitity  and  practicability  of  such  investigations.  There  is,  moreover, 
an  urgent  demand  for  such  studies  from  economic  entomologists,  who  are 
constantly  confronted  by  the  problem  of  identifying  the  immature  stages 
of  economic  species. 

The  present  study  is  an  attempt  to  deal  with  the  larvae  of  the  Ten- 
thredinoidea  from  the  standpoint  of  synoptic  and,  to  some  extent,  genetic 
classification.  The  systematic  significance  of  the  morphological  charac- 
ters will  be  discussed  in  part  two;  the  taxonomic  treatment  of  the  families, 
subfamilies,  genera,  and  species  will  constitute  part  three;  and,  as  full  a 
discussion  of  the  phylogenetic  relationship  of  the  families  as  is  possible 
with  the  data  at  hand,  will  form  part  four.  No  one  appreciates  the  inade- 
quacy of  this  study,  both  in  thoroughness  and  comprehensiveness,  more 
than  the  author,  but  it  is  hoped  that  he  has  opened  a  way  for  those  who 
will  advance  our  knowledge  of  this  highly  interesting  group  of  insects  to 
a  more  satisfactory  condition  in  the  future. 

The  taxonomic  literature  dealing  with  the  adults  of  the  Tenthredinoidea 
is  extensive.  The  historical  development  of  the  subject  is  interesting  to 
students  of  this  group  of  insects  but  a  detailed  account  is  out  of  place  here. 
However,  a  brief  statement  of  the  history  of  the  group  is  desirable. 


8  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [326 

Linnaeus  in  the  fourth  edition  of  the  Systema  Naturae  (1744)  estab- 
lished the  order  Hymenoptera  under  the  name  of  Gymnoptera  and  applied 
to  the  order  its  present  designation  in  the  first  edition  of  the  Fauna  Suecica. 
The  name  Piezata  was  proposed  by  Fabricius  (1775)  for  the  order,  but 
this  name  never  came  into  general  use.  Latreille  (1796),  following  Lin- 
naeus, divided  the  order  into  two  sections,  Terebrantia  and  Aculeata. 
The  first  section  included  two  groups,  Phytophaga,  which  comprises  the 
Tenthredinoidea,  and  the  Entomophaga  or  parasitic  Hymenoptera.  The 
Ditrocha  and  Monotrocha  of  Hartig  (1837)  correspond  approximately 
with  the  two  sections  of  Latreille.  Gerstaecker  clearly  recognized  the 
Tenthredinoidea  as  a  unique  compact  group  and  proposed  in  1867  to 
divide  the  order  Hymenoptera  into  two  suborders.  He  used  the  name 
Symphyta  for  the  Tenthredinoidea  and  Apocrita  for  the  remainder  of  the 
order.  The  term  Symphyta  thus  antedates  Konow's  (1890)  subordinal 
name  Chalastogastra.  Various  terms  have  been  proposed  for  this  group 
of  Hymenoptera  and  the  following  are  coextensive  with  the  superfamily 
name  Tenthredinoidea  as  used  in  the  present  paper:  Phytophaga,  Ses- 
siliventres,  Securifera,  Serrifera,  Symphyta,  and  Chalastograstra.  Rohwer 
and  Cushman  (1917)  proposed  a  third  suborder  of  Hymenoptera,  Idiogas- 
tra,  for  the  family  Oryssidae  and  placed  it  between  the  Chalastogastra  and 
Clistogastra  of  Konow. 

Early  students  of  the  Tenthredinoidea  divided  the  superfamily  into 
two  groups,  Phyllophaga  for  the  Tenthredinidae  or  "Tenthredo"  of 
Linnaeus  and  Xyllophaga  for  the  Siricidae  or  "Urocerus"  of  Geoffroy. 
With  the  exception  of  Stephens  (1835)  and  Andre"  (1879),  who  recognized 
the  additional  families  Xiphydriidae  and  Cephidae,  respectively,  besides 
the  two  families  mentioned  above,  the  old  system  was  followed  for  many 
years.  With  the  progress  in  studies  of  the  world  fauna  of  this  group 
of  insects,  modern  writers  h<ave  proposed  many  elaborate  schemes  of  classi- 
fication. Konow  in  1890  suggested  one  family  and  three  subfamilies  and 
Dalla  Torre  (1894)  catalogued  one  family  divided  into  eighteen  subfamilies, 
while  Ashmead  (1898)  proposed  fifteen  families  and  twenty-seven  sub- 
families. Enslin  (1911)  criticized  Konow's  three  divisions  as  unnatural 
and  proposed  four  families,  Oryssidae,  Siricidae,  Cephidae,  and  Tenth- 
redinidae, thus  reverting  to  a  considerable  extent  to  the  scheme  of  the  old 
school  as  represented  by  Cameron  (1882)  and  others.  The  recent  and 
more  important  systems  are  those  proposed  by  Konow  (1905),  MacGilliv- 
ray  (1906),  and  Rohwer  (1911).  These  systems,  when  compared,  show  a 
great  discrepancy  in  the  number  and  rank  of  the  groups  which  formerly 
constituted  the  family  Tenthredinidae,  as  is  indicated  graphically  in 
Plate  XIV.  MacGillivray,  whose  classification  is  based  on  a  thoro-going 
phylogenetic  study  of  the  wings,  is  of  the  opinion  that  the  large  complex 
of  genera  obtained  in  this  family  are  readily  separable  into  a  number  of 


3271  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  9 

definite  groups  on  structural  differences,  and  that  they  are  best  dealt 
with  by  considering  them  simply  as  subfamilies.  In  general  the  systems 
of  Konow  and  Rohwer  are,  with  the  exceptions  noted  below,  more  in 
accordance  with  each  other  in  their  essential  features  than  either  one  of 
them  is  with  that  of  MacGillivray.  A  comparison  of  these  three  schemes 
brings  out  various  points  of  interest.  As  far  as  the  major  groups  are  con- 
cerned, (1)  all  are  in  agreement  in  associating  Xiphydriidae  with  Siricidae; 
(2)  Konow  and  Rohwer  agree  in  placing  Siricidae  and  Siricoidea  closer  to 
Lydidae  and  Megalodontoidea  respectively  than  does  MacGillivray,  as 
also  in  associating  Megalodontidae  with  Pamphiliidae  and  Xyelidae  and 
Pamphiliidae  with  Cephidae;  (3)  Konow  and  MacGillivray  agree  in  the 
relation  of  the  Blasticotomidae  to  Xyelidae  and  Pamphiliidae;  (4)  Rohwer 
differs  radically  from  them  in  his  arrangement  of  the  Blasticotomidea, 
which  he  places  between  the  Argidae  and  Tenthredinidae  in  his  super- 
family  Tenthredinoidea;  and,  finally  (5),  Rohwer  (1917)  is  unique  in 
creating  a  third  suborder  of  Hymenoptera,  Idiogastra,  for  the  Oryssidae. 
In  respect  to  the  arrangement  of  the  subfamilies  and  tribes  of  the  Tenth- 
redinidae, as  restricted  by  MacGillivray,  the  striking  dissimilarity  of  these 
authorities  in  assigning  different  rank  to  more  or  less  related  groups  is 
well  illustrated  in  their  treatment  of  the  Emphytinae,  Selandriinae,  and 
Lycaotinae.  According  to  MacGillivray  Konow's  tribe  Selandriades  of  his 
family  Tenthredinini  corresponds  to  the  three  subfamilies  just  mentioned, 
while  according  to  Rohwer  it  embraces  not  only  these  subfamilies  but  also 
another — Allan tinae;  that  is,  Rohwer  considers  the  Emphytinae  related 
to  the  Tenthredinidae  thru  the  tribe  Allantini,  which,  together  with  the 
tribes  Taxonini  and  Eriocampini,  constitute  his  subfamily  Allantinae. 
The  Emphytinae  and  Lycaotinae  are  also  related,  according  to  Rohwer, 
to  the  Blennocampinae  thru  his  subfamily  Empriinae,  which  contains, 
besides  Empriini  and  Lycaotini,  the  tribe  Blennocampini.  MacGillivray 
and  Rohwer  agree  in  regard  to  the  Cimbicinae  to  the  extent  that  they 
both  consider  it  a  compact  group.  Konow  differs  radically  from  these 
writers  by  associating  his  tribe  Syzygoniides  with  the  Cimbicides  and 
Abiides.  In  regard  to  Konow's  Nematides  and  Lobocerotides,  the  three 
systems  agree  fairly  well.  The  affinities  of  the  Blennocampinae,  Fenusinae, 
and  Scolioneurinae  are  recognized  by  MacGillivray  and  Konow.  Rohwer 
and  Konow  agree,  as  do  all  other  systematists  except  MacGillivray,  in 
treating  the  Diprioninae  and  Monocteninae  as  allied  groups  inseparable 
into  subfamilies.  Konow's  subfamily  Lophyrini,  however,  is  a  hetero- 
geneous group  and  includes  such  widely  separated  groups  as  Acordule- 
cerinae  and  Diprioninae. 

The  classification  proposed  by  MacGillivray  is  based  upon  a  critical 
investigation  of  an  essential  structure,  the  wing,  and  is  a  logical  conclusion 
of  the  application  of  the  taxonomic  principles  promulgated  by  Comstock 


10  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (328 

(1893).  This  system  of  classification  is  adopted  in  principle  in  the  present 
paper,  for  the  writer  believes  that  by  judicious  discrimination  between  the 
palingenetic  and  the  cenogenetic  peculiarities,  the  characters  manifested 
by  immature  insects  may  be  interpreted  as  indicating  the  genetic  affinities 
of  the  insects  under  consideration,  and  that  in  this  sense  the  immature 
stages  of  insects  are  of  systematic  importance.  A  classification  based  upon 
such  larval  characters  should  agree  in  essential  points  with  that  based 
upon  the  adult  characters  chosen  for  their  phylogenetic  value,  and  there- 
fore it  is  interesting  to  see  whether  MacGillivray's  alary  system  is  justified 
by  a  study  of  the  larvae.  It  must  be  stated  here  that  Dr.  MacGillivray 
does  not  accept  all  my  conclusions  as  to  the  relation  of  the  families  based 
upon  a  study  of  the  larvae. 

The  immature  stages  of  the  Tenthredinoidea  of  more  common  occur- 
rence seem  to  have  attracted  the  attention  of  naturalists  from  an  early 
time.  In  Moufet's  Theatorum  Insectorum  (1634)  the  adult  saw-flies 
are  referred  to  the  group  "Vespa"  and  what  seems  to  be  a  Tremex  to 
"Odonata,"  but  no  mention  of  the  larvae  is  made.  Goedart  (1682)  was 
the  first  naturalist  to  make  observations  on  the  larvae  of  a  saw-fly.  His 
records,  rendered  in  interesting  archaic  terms,  clearly  indicate  that  he  had 
under  observation  the  larvae  of  Cimbex  or  Trichiosoma  on  Salix,  and  Arge 
on  Rosa.  Madame  Merian  (1730)  pictured  saw-fly  larvae  together  with 
those  of  the  Lepidoptera,  as  may  be  seen  on  her  plates  22,  25,  and  33. 
Swammerdamm's  (1737)  figure  1,  table  XLIV,  refers  to  galls  on  the 
leaves  and  stems  of  Salix  apparently  made  by  Pontania  or  Euura.  He 
also  figured  a  larva  having  fifteen  segments  with  larvapods  on  abdominal 
segments  3-8  and  11.  Frisch  (1766)  figured  about  seven  species  and 
recorded  observations  on  their  life-history.  De  Geer,  as  cited  by  Bergmann, 
on  the  authority  of  Le  Peletier  (1823),  had  seen  a  larva  with  twenty- 
two  feet  exclusive  of  the  anal  larvapods.  According  to  the  same  authority, 
Reaumur  observed  certain  larvae  with  twenty-four  feet,  indicating  a 
xyelidan  condition.  Linnaeus  (1758)  recorded  the  food-plants  of  twenty- 
two  species  of  saw-flies  out  of  the  forty  species  of  "Tenthredo"  enumer- 
ated, and  spoke  of  the  larvae  in  general  of  "Tenthredonis  larvae  pleraeque 
folia  plantarum  exedunt,  polypodae,  seu  pedibus  plus  quam  XVI  com- 
muniter  instructae."  Following  Linnaeus  many  students  of  the  Tenthre- 
dinoidea contributed  much  to  a  knowledge  of  the  immature  stages,  altho 
quite  disproportionately  to  their  larger  contributions  to  that  of  the  adults. 
Among  those  who  have  done  much  towards  the  progress  of  our  knowledge 
of  the  larvae,  either  as  original  investigators  or  as  compilers  or  as  both, 
the  following  are  the  more  important:  Andre,  Brischke,  Cameron,  Costa, 
Dahlbom,  Dalla  Torre,  Dufour,  Dyar,  Fallen,  Hartig,  Kaltenbach,  Kirby, 
Klug,  Konow,  Latreille,  Leach,  Middleton,  Newman,  Oliver,  Panzer, 
Le  Peletier,  Snellen  von  Vollenhoven,  Spinola,  Westwood,  and  Zaddach. 


329}  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  11 

Still,  our  knowledge  of  the  immature  stages  of  the  Tenthredinoidea  is 
very  meager  in  comparison  to  that  of  the  adult.  The  larvae  of  only 
418  species  out  of  the  total  of  2701  species  listed  by  Konow  in  his  mono- 
graph (1905)  were  dealt  with  in  his  artificial  table  for  the  larvae.  This  was 
less  than  sixteen  per  cent  of  the  described  species  of  the  world  up  to  his 
time,  and  many  larvae  included  in  this  sixteen  per  cent  were  known  to 
this  authority  only  thru  literature.  According  to  Dyar  (1895)  less  than 
twenty-five  per  cent  of  the  North  American  species  have  been  recognized 
in  the  larval  state.  It  is  no  exaggeration  to  say  that  the  larvae  of  more 
than  eighty  per  cent  of  the  Nearctic  species  are  yet  to  be  described. 

Our  knowledge  of  the  physiology  and  morphology  of  the  immature 
stages  of  the  Tenthredinoidea  is  exceedingly  meager.  The  following  list 
includes  most  of  the  important  literature:  Graber  (1890)  on  the  embry- 
ology of  Arge  berberides;  Doncaster  (1907)  on  the  gametogenesis  and 
fertilization  in  Nematus  ribesi;  Biichner  (1918)  on  the  accessory  chromo- 
somes in  Tenthredo,  Allantus,  Arge,  etc.;  Frenzel  (1885)  on  the  epithelial 
regeneration  of  the  alimentary  canal  of  the  larva  of  Cimbex;  Holtz  (1909) 
on  the  histology  and  physiology  of  the  digestive  cells  in  the  larva  of 
Nematus;  Poletajew  (1885)  on  the  silk-glands  of  the  larvae  of  Cimbex 
and  Tenthredo;  Cholodkovsky  (1897)  on  the  blood  and  reflex  bleeding  of 
the  larva  of  Cimbex;  and  MacGillivray  (1913)  on  the  general  external 
anatomy  of  the  larvae. 

The  biology  of  the  Tenthredinoidea  abounds  in  phenomena  of  great 
interest  to  experimental  evolutionists  and  presents  many  problems  of  eco- 
logical importance.  The  list  of  papers  dealing  with  the  life-history  and 
habits,  especially  of  economic  species,  is  fairly  extensive.  Cameron 
(1882)  has  published  an  excellent  summary  of  general  biological  and 
ecological  observations.  The  biology  of  the  Nearctic  Tenthredinoidea 
has  been  discussed  in  detail  by  MacGillivray  (1913).  Since  the  biological 
and  ecological  studies  of  the  Tenthredinoidea  are  beyond  the  scope  of  the 
present  paper,  readers  are  referred  to  the  last-mentioned  publication. 

Materials. — Four  collections,  designated  for  convenience  as  the  Cor- 
nell, Maine,  MacGillivray,  and  Yuasa  collections,  contain  most  of  the 
materials  used  in  this  study.  The  writer  has  examined  more  than  2500 
alcoholic  specimens  of  larvae  representing  at  least  400  species  during 
the  course  of  this  study.  He  has  also,  during  the  last  few  years,  at  Ithaca, 
N.  Y.,  and  at  Urbana,  111.,  made  observations  on  the  life-history  and 
habits  of  numerous  species  in  his  attempts  to  breed  more  than  two  hundred 
and  fifty  species. 

The  Cornell  collection  consists  of  about  forty  species  and  belongs  to 
the  Cornell  University.  Most  of  the  specimens  were  collected  by  Dr. 
MacGillivray  and  Mr.  Chester  Young  in  the  vicinity  of  Ithaca,  N.  Y. 
They  were  in  rather  a  poor  state  of  preservation  and  proved  useful  only 


12  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (330 

in  checking  up  materials  in  other  collections  and  in  comparing  the  de- 
scriptions of  Young  with  his  own  material.  This  collection  is  designated 
by  the  letter  C. 

The  Maine  collection  consists  of  about  200  species,  many  of  which  were 
bred  and  identified  by  Dr.  MacGillivray.  The  collection  belongs  to  the 
Maine  Agricultural  Experiment  Station  and  all  the  specimens  were  in 
excellent  condition.  They  were  collected  by  Dr.  MacGillivray  with  the 
assistance  of  Mr.  Earl  Shaw  during  the  summer  of  1913  in  the  vicinity  of 
Orono,  Maine.  This  collection  together  with  the  collecting  and  breeding 
records  were  placed  in  the  writer's  hands,  and  they  proved  to  be  indis- 
pensable to  the  present  study.  The  collection  is  designated  by  the  letter 
M. 

The  MacGillivray  collection  consists  of  about  thirty-five  species 
collected  and  identified  by  Dr.  MacGillivray,  together  with  larvae  of 
some  unidentified  species.  The  specimens  came  from  Ithaca,  N.  Y., 
Orono,  Me.,  Onekama,  Mich.,  Urbana,  111.,  and  a  few  other  localities. 
This  collection  is  designated  by  the  letter  G. 

The  Yuasa  collection  consists  of  about  two  hundred  and  thirty  species 
including  98  bred  species.  A  majority  of  the  specimens  were  collected  by 
the  writer  at  Ithaca,  N.  Y.,  during  the  summers  of  1917  and  1918.  Some 
species  were  collected  at  Urbana,  111.,  and  others  came  from  different 
parts  of  the  United  States  and  Canada  thru  the  generosity  of  various 
entomologists.  This  collection  contains  also  the  cocoons  of  practically  all 
the  bred  cocoon-making  species  and  eggs  and  pupae  of  a  limited  number  of 
species.    This  collection  is  designated  by  the  letter  Y. 

Besides  the  four  collections  just  mentioned,  a  number  of  rare  speci- 
mens were  generously  loaned  to  me  by  several  people,  as  subsequently 
acknowledged,  and  were  of  great  value  in  the  preparation  of  this  paper. 

Identification. — All  bred  species  in  the  Maine,  MacGillivray  and 
Yuasa  collections  were  identified  by  Dr.  MacGillivray.  Some  of  the 
specimens  in  the  Cornell  collection  bore  labels,  and  when  the  larvae  agreed 
satisfactorily  with  the  published  descriptions  the  identifications  were 
accepted.  In  only  a  few  cases  has  identification  depended  solely  on 
published  descriptions  of  larvae. 

Terminology  and  Nomenclature. — For  the  description  of  the  external 
anatomy  of  the  head  and  mouth-parts  of  the  larvae  the  terms  used  in  my 
paper  (1920)  dealing  with  the  generalized  insects  have  been  used.  Other 
terms,  some  new,  are  used  in  part  II.  Taxonomic  names  have  been 
adopted  from  Rohwer  (1911)  and  MacGillivray  (1906). 

Bibliography. — Works  on  taxonomic  units  are  omitted  altogether.  A 
complete  bibliography  of  the  Nearctic  Tenthredinoidea  was  not  under- 
taken owing  to  space  limitations,  but  the  most  important  literature  on 
the  subject  is  listed,  as  also  that  cited  in  the  text. 


331]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  13 

Acknowledgments. — I  am  deeply  indebted  to  various  scientists  who 
have  assisted  me  by  donation  of  specimens,  by  encouragement,  and  by 
criticism  and  suggestions.  I  am  obliged  to  the  former  Director  of  the 
Maine  Agricultural  Experiment  Station,  C.  D.  Wood,  and  to  Dr.  Edith 
Patch  of  the  same  Station;  to  Dr.  J.  Chester  Bradley,  of  the  Cornell 
University,  and  to  Professor  S.  A.  Forbes,  of  the  University  of  Illinois,  for 
the  loan  of  specimens  and  for  the  privilege  of  examining  collections  under 
their  charge.  I  wish  to  thank  Dr.  J.  G.  Needham  for  the  privilege  of 
working  in  the  entomological  laboratories  of  Cornell  University  during  the 
summers  spent  at  Ithaca,  and  Mr.  S.  A.  Rohwer,  of  the  U.  S.  Bureau 
of  Entomology,  Washington,  D.  C,  for  his  generous  criticism  and  for  the 
donation  of  valuable  reprints.  I  am  also  indebted  for  separates  to  Dr.  W. 
E.  Britton,  and  to  Messrs.  H.  E.  Burke  and  William  Middleton;  for  the 
donation  of  specimens,  to  Messrs.  H.  G.  Crawford,  Wm.  Baerg,  C.  C. 
Hamilton,  R.  W.  Harned,  J.  W.  McColloch,  J.  R.  Malloch,  H.  S.  Smith, 
H.  B.  Weiss,  and  to  Drs.  W.  E.  Britton,  C.  H.  Kennedy,  Edna  Mosher,  and 
Alvah  Peterson;  and  for  the  loan  of  rare  specimens  of  Cephidae  and  Xiphy- 
dria,  and  of  Monoctenus  and  Trachelus  to  Dr.  E.  P.  Felt  and  Mr.  S.  A. 
Rohwer,  respectively.  I  take  pleasure  in  acknowledging  my  deep  in- 
debtedness to  Dr.  Albert  William  Bellamy,  of  the  University  of  Chicago, 
for  constant  encouragement.  I  am  greatly  obliged  to  Professor  William 
Trelease,  of  the  University  of  Illinois,  and  to  Professor  K.  M.  Wiegand 
and  Mr.  A.  R.  Bechtel,  of  the  Cornell  University,  for  the  identification 
of  the  host-plants.  It  gives  me  great  pleasure  to  acknowledge  my  lasting 
obligation  to  Professor  Alexander  Dyar  MacGillivray,  under  whose 
supervision  this  work  was  undertaken,  for  his  constant  interest,  encour- 
agement, and  helpful  suggestions  thruout  the  entire  course  of  this  study 
and  for  identifying  all  of  the  bred  specimens  in  my  collection,  as  well  as 
for  the  privilege  of  using  his  unpublished  morphological  terminology. 


14  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [332 


II.     MORPHOLOGY 

The  external  anatomy  of  the  larvae  of  the  Tenthredinoidea  has  received 
but  little  attention  from  entomologists.  The  only  important  contribution 
on  the  subject  is  MacGillivray's  study  (1913),  which  deals  with  the  anat- 
omy and  coloration  as  well  as  with  the  biology  of  the  larvae.  The  writer 
has  made  a  comparative  study  of  the  external  anatomy  of  the  larvae  of 
representative  Nearctic  Tenthredinoidea  in  order  to  find  characters  upon 
which  both  analytic  and  synoptic  classifications  of  the  larvae  might  be 
based.  Since  MacGillivray  has  treated  the  general  aspect  of  the  anatomy, 
only  the  more  important  structures  and  features  will  be  discussed  in  the 
following  pages. 

The  larvae  of  the  Tenthredinoidea  (Figs.  1-25)  are  typically  subcylin- 
drical,  eruciform,  caterpillar-like,  slightly  flattened  on  the  ventral  aspect, 
and  usually  taper  slightly  caudad.  In  the  leaf-miners  the  body  is  de- 
pressed. The  body  in  its  metamerism  is  well  differentiated  into  a  head 
and  a  series  of  thirteen  somites  which  are  more  or  less  similar  in  structure. 
The  segmentation  is  distinct.  The  first  three  segments  compose  the 
thorax  and  are  distinguishable  on  account  of  their  position,  form,  and, 
in  podous  larvae,  more  readily  by  the  presence  of  three  pairs  of  thoracic 
legs.  The  abdomen  consists  of  the  ten  remaining  visible  segments  and  in 
polypodous  larvae  the  presence  of  larvapods  gives  a  characteristic  appear- 
ance to  the  uromeres.  They  are  usually  subdivided  by  transverse  depres- 
sions into  annulets. 

Head. — The  head  (Figs.  26-38)  is  typically  subglobose,  more  or  less 
circular  in  frontal  contour,  strongly  chitinized,  and  usually  setiferous. 
The  mouth  is  directed  ventrad  or  slightly  ventro-caudad.  In  the  leaf-min- 
ers it  is  directed  cephalo-ventrad  as  in  the  Fenusinae  (Fig.  34)  or  cephalad 
as  in  Phlebatrophia  (Fig.  37).  The  surface  of  the  head  may  be  polished 
and  shiny  as  in  Neodiprion  (Fig.  28),  or  roughened,  verrucose,  or  granu- 
late, and  divided  into  minute  irregular  areas  as  in  Pteronidea  (Fig.  30) 
and  the  Cimbicinae  (Fig.  29),  or,  in  life,  thinly  coated  with  a  waxy  secretion, 
as  in  some  Emphytinae.  It  may  be  glabrous  as  in  Metallus  (Fig.  35)  and 
Phlebatrophia  (Fig.  37),  or  it  may  be  variously  setiferous  as  follows: 
microscopically  and  sparsely  setiferous  as  in  Tremex;  with  a  few  scattering 
setae  as  in  the  Phyllotominae;  with  minute  stiff  peg-like  setae  as  in  Neodi- 
prion; with  numerous  promiscuously  distributed  short  setae  as  in  Dolerus 


333]  T.ARVAE  OF  THE  TENTHREDINOIDEA—YUASA  15 

and  the  Tenthredininae;  with  long  setae  as  in  Pteronidea;  or  with  abund- 
ant conspicuous  setae  as  in  Monophadnoides  and  the  Cladiinae.  The 
setae  tend  to  be  more  numerous  and  longer  on  the  ventral  portion  of  the 
head.  The  number  and  location  of  the  setae  on  the  head  vary  with  the 
individuals,  excepting  those  on  the  clypeus  and  labrum,  but  their  general 
characteristics,  such  as  relative  abundance,  manner  of  distribution, 
and  the  kind  of  setae,  are  constant  within  genera  and  subfamilies.  The 
head  may  be  pale,  creamy  white,  or  light  brown,  but  often  in  life  appears 
as  green  or  greenish  white  on  account  of  the  greenish  blood  showing  thru 
the  cuticle,  or  it  may  be  blackish  or  brownish  with  or  without  distinct  color- 
markings.  The  darker  color  is  due  to  a  deposition  of  colored  pigments  in 
the  cuticle  and  is  generally  permanent  in  alcoholic  specimens.  The  color 
and  the  coloration  of  the  head  are  generally  constant  specific  characters. 
There  are,  however,  ontogenetic  changes  in  these  respects.  The  very  young 
stages  may  be  lighter  in  color  and  later  stages  darker,  or  vice  versa  as  in 
Cimbex,  or  all  stages  except  the  last  instar  may  be  darker  and  the  ultimate 
stage  greenish  as  in  Pteronidea  ribesii.  The  color  markings  may  be  diffuse 
in  the  young  and  become  localized  and  definite  in  older  stages,  as  in  some 
species  of  Dolerus,  or  they  may  vary  from  faint  spots  to  general  contiguous 
markings  as  in  certain  species  of  Strongylogaster.  The  more  common  mark- 
ings are  brownish  spots  on  the  dorsum  of  the  vertex,  on  the  front,  and  often 
caudad  of  each  ocellera.  There  may  be  a  stripe  along  the  epicranial  stem 
and  vertical  furrows  or  dorsad  of  the  ocellarae.  When  the  head  is  darkly 
colored  the  clypeus  is  usually  lighter  in  color  than  the  other  parts  of  the 
head. 

The  head  is  usually  exposed,  but  there  is  a  tendency  in  the  leaf-miners, 
wood-borers,  and  a  few  others  to  have  the  cephalic  end  of  the  prothorax 
produced  into  a  broad  fold  on  the  dorsal  and  lateral  aspects.  This  fold 
covers  the  caudal  portion  of  the  head  as  in  Tremex,  Metallus  (Fig.  35), 
and  Caliroa  (Fig.  69). 

The  structures  of  the  head  will  be  discussed  under  two  sections,  one 
dealing  with  the  fixed  parts,  that  is  all  the  immovable  parts  of  the  head- 
capsule,  and  the  other  dealing  with  the  movable  parts — the  antennae  and 
mouth-parts.  The  fixed  parts  include  the  vertex,  front,  clypeus,  labrum, 
occiput,  and  postgenae,  together  with  their  bounding  sutures,  ocellarae, 
and  tentoria. 

Epicranial  Suture. — The  inverted  Y-shaped  median  suture  of  the  head 
is  the  epicranial  suture.  The  stem  (es)  of  the  Y  originates  at  the  occipital 
foramen,  extends  cephalad,  dividing  the  vertex  into  halves,  and  bifurcates 
on  the  cephalic  aspect  of  the  head.  Each  arm  of  the  bifurcation  (ea) 
extends  obliquely  laterad  for  a  short  distance  and  then  bends  ventrad 
to  the  ventral  margin  of  the  head,  terminating  near  a  precoila.  The 
epicranial  suture  is  present  in  all  larvae  except  those  of  the  Xiphydriidae 


16  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [334 

(Fig.  45),  where  it  is  in  part  indistinct,  and  in  the  Siricidae  and  Oryssidae, 
where  it  is  obsolete.  It  is  interesting  to  note  that  the  most  highly  special- 
ized genus  of  the  Tenthredinidae,  Phlebatrophia  (Fig.  37),  possesses  this 
suture.  The  relative  length  of  the  stem  and  arms  varies  in  different 
families  and  subfamilies.  There  is  a  depression  near  the  bend  of  the  arm, 
as  in  Lygaeonematus  (Fig.  31),  which  indicates  the  point  of  attachment  of 
muscles  (ma),  and  should  not  be  confused  with  a  true  tentorina  (/>«). 
Near  the  ventral  end  of  each  epicranial  arm  there  is  a  thickening  of  the 
surface  and  a  pit.  This  pit  is  a  pretenorina  (/>«)  and  the  thickened  piece 
corresponds  to  the  clypealia  (cl)  of  the  larva  of  Corydalis.  The  preten- 
torina  and  clypealia  are  constant  in  position  and  universal  in  occurrence  in 
the  Tenthredinoidea.  In  the  Siricidae  the  pretentorinae  are  distinct  and 
sometimes  mistaken  for  ocellarae.  In  ecdysis  the  head  is  split  along  the 
epicranial  suture  nearly  to  the  ventral  ends  of  the  arms. 

Vertex. — The  large  area  on  each  side  of  the  epicranial  stem  is  the  vertex 
(v).  It  extends  from  the  dorso-meson  of  the  epicranium  to  the  ventral 
margin  of  the  head,  laterad  of  the  epicranial  arm,  and  cephalad  of  the 
occipital  suture  when  this  is  present,  and  bears  an  ocellara  (o)  and  anten- 
naria  (ar).  There  is  on  the  dorsal  part  of  the  vertex  on  each  side  a  distinct 
furrow  which  originates  at  the  occipital  foramen  and  extends  cephalad 
for  some  distance  onto  the  lateral  aspect  of  the  head.  This  is  the  vertical 
furrow  (vf)  and  is  characteristic  of  the  larvae  of  the  Tenthredinoidea. 
It  is  wanting  only  in  the  leaf-miners  and  wood-borers.  The  nature  of  this 
furrows  is  not  known.  There  is  a  corresponding  carina  on  the  ental  sur- 
face of  the  head,  and  the  major  muscles  of  the  retractor  of  the  mandible 
are  attached  to  the  ental  surface  of  the  vertex  dorsad  and  ventrad  of  the 
vertical  furrow.  The  furrows  usually  converge  at  the  cephalic  end,  but 
sometimes  are  subparallel  to  each  other. 

Genae. — The  portion  of  the  vertex  ventrad  of  an  imaginary  line  drawn 
ventrad  of  each  ocellara  parallel  to  the  ventral  margin  of  the  head  is  a 
gena  (g).  The  extent  of  the  genae  varies,  therefore,  according  to  the 
location  of  the  ocularia.  The  setae  on  the  genae  are  sometimes  longer 
than  those  elsewhere. 

Ocularia. — The  larvae  of  the  Pamphiliidae,  Xyelidae,  Tenthredinidae, 
and  Cephidae  possess  a  pair  of  ocellarae  (e),  one  on  each  side  of  the  head. 
These  organs  of  sight  are  remarkably  uniform  and  constant  in  structure 
and  location.  With  the  exception  of  Phlebatrophia  and  the  Cephidae,  the 
ocellarae  are  usually  clear,  semiglobose  or  at  least  distinctly  convex, 
and  are  located  on  or  near  the  center  of  the  ocularia  {ou),  which  are  usually 
circular  and  distinctly  blackish.  The  ocularia  are  located  on  the  vertex 
dorsad  of  the  antennariae  in  the  Tenthredinidae  and  caudad  of  them 
in  the  Pamphiliidae  and  Cephidae.  In  the  Cephidae  and  Phlebatrophia 
the  ocularia  are  obsolete  and  the  ocellarae  are  indicated  by  pigmented 


335]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  17 

granules  showing  thru  the  cuticle.  The  ocellarae  are  obsolete  in  the 
highly  specialized  families,  Xiphydriidae  and  its  allies.  The  life-habits 
are  correlated  with  the  presence  and  the  degree  of  development  of  the 
organs  of  sight. 

Front. — The  area  bordered  by  the  epicranial  arms  on  the  cephalic  aspect 
of  the  head  is  the  front  ([/").  The  ventral  boundary  is  indicated  by  a 
transverse  depression  connecting  the  ventral  ends  of  the  epicranial  arms. 
This  depression  is  the  fronto-clypeal  suture  (Jcs).  The  depression  is 
usually  concave  dorsad  and  often  obsolete  at  each  lateral  end.  The 
front  is  usually  flattened  or  only  slightly  convex  and  bears  scattered  setae 
which  vary  in  number  and  arrangement  in  different  genera  and  in  arrange- 
ment in  different  individuals.  The  extent  of  the  front  is  determined  by 
the  length  of  the  epicranial  arms.  The  front  is  usually  subquadrate, 
often  wider  than  1  ong,  but  in  some  cases,  as  in  Caliroa  (Fig.  53),  it  is 
much  longer  than  wide.  In  the  absence  of  the  epicranial  stem  the  lateral 
boundaries  are  indicated  by  the  pretentorinae  as  in  Tremex  (Fig.  46). 
Phlebatrophia  (Fig.  37)  is  unique  in  possessing  a  distinct  median  longi- 
tudinal furrow  on  the  dorsal  half  of  the  front. 

Clypeus. — The  area  ventrad  of  the  front  is  the  clypeus  (c).  Its  ventral 
boundary  is  the  clypeo-labral  suture  (ds),  and  the  lateral  margins  are  free, 
oblique,  and  converge  ventrad.  The  clypeus  is  usually  much  wider  than 
long  and  is  divided  usually  into  postclypeus  (po)  and  preclypeus  (pe)  by  a 
difference  in  color  and  by  a  transverse  row  of  setae.  Sometimes  the 
clypeal  suture  (cs)  is  distinct,  as  in  some  Nematinae  (Fig.  31).  The  clypeal 
setae  vary  in  number  from  two  to  eight  or  ten  but  are  constant  within  a 
genus  and  often  within  a  subfamily.    Four  is  the  most  common  number. 

Labrutn. — The  small  lobe  attached  to  the  ventral  margin  of  the  clypeus 
is  the  labrum  (l).  It  is  usually  transverse  and  has  a  median  emargination 
on  the  ventral  margin.  This  emargination  is  usually  shallow  and  broad 
but  occasionally  very  deep,  as  in  Eriocampa  and  a  few  other  Emphytinae. 
Dolerus  (Fig.  42)  is  characterized  by  the  distinct  asymmetrical  median 
emargination  which  makes  the  sinistral  half  of  the  labrum  much  smaller 
than  the  dextral.  The  cephalic  margin  is  nearly  smooth  and  slightly 
oblique  in  Tremex  (Fig.  46).  The  labrum  is  very  small  in  the  Xiphydriidae 
(Fig.  45).  From  two  to  several  labral  setae  (Is)  are  borne  on  each  side 
of  the  meson,  those  near  the  meson  being  usually  smaller  than  the  lateral 
ones.  The  number  of  labral  setae  are  as  a  rule  constant  within  a  genus. 
A  row  of  setae  which  may  be  seen  projecting  from  the  ventral  surface  of  the 
labrum  belongs  to  the  epipharynx.  The  labrum  is  often  divided  into 
halves  by  a  distinct  median  longitudinal  depression,  as  in  Caliroa  (Fig.  53), 
Endelomyia  (Fig.  48),  and  some  Tenthredininae.  This  character  is  generic 
in  some  subfamilies  and  only  specific  in  others.    The  labrum  in  the  Cim- 


18  ILLINOIS  BIOLOGICAL  MONOGRAPHS     .   .  (336 

bicinae  (Fig.  29)  is  unique  in  having  a  pair  of  longitudinal  depressions  on 
each  half  which  converge  ventrad  and  bound  a  small  median  piece. 

Postgenae. — The  area  mesad  of  the  lateral  boundary  of  the  vertex  on 
the  caudal  aspect  of  the  head  is  the  postgena  (pa).  The  dorsal  boundary- 
is  the  vertical  furrow  and  the  mesal  the  occipital  foramen.  The  ventral 
margin  is  concave  and  is  connected  with  the  labicoria  (Ic).  It  is  usually 
more  or  less  flat  and  glabrous.  The  occipital  suture  (os)  is  sometimes 
distinct,  as  in  Pteronidea. 

Tortnae. — At  each  end  of  the  clypeo-labral  suture  there  is  a  chitinized 
rod  which  extends  onto  the  ventral  surface  as  far  as  the  epigusta.  This  is 
the  torma,  present  in  all  Tenthredinidae. 

Occiput.— The  narrow  area  on  the  dorsal  third  of  the  occipital  foramen 
between  the  vertical  furrows  is  the  occiput.  The  dorsal  boundary  is  in- 
distinct since  the  occiput  merges  with  the  vertex  without  any  indication 
of  a  suture. 

Maxillariae. — The  very  narrow  chitinized  sclerites  which  form  a  sub- 
circular  collar  around  the  dorsal  and  lateral  margins  of  the  occipital 
foramen  have  been  identified  as  the  maxillariae  (my).  They  are  usually 
only  slightly  developed  and  are  continuous  with  the  cervacoria.  The 
identity  of  these  sclerites  with  the  maxillariae  of  generalized  adult  insects 
is  uncertain,  but  they  occupy  the  same  position  as  the  maxillariae  and 
consequently  are  considered  as  homologous  with  them.  The  dorsal  third  of 
the  maxillariae  in  the  leaf-miners  Metallus  (Fig.  35),  Phlebatrophia  (Fig. 
37)  and  Fenusinae  (Fig.  34),  are  strongly  chitinized,  distinctly  concave, 
trough-like,  and  produced  en  tad.  Along  this  ental  margin  a  part  of  the 
muscles  which  control  the  movement  of  the  head  are  attached. 

Occipital  Foramen. — The  large  opening  in  the  caudal  aspect  of  the 
head  thru  which  the  internal  organs  of  the  head  are  connected  with  those 
of  the  body  is  the  occipital  foramen  (of).  The  ventral  margin  of  the 
occipital  foramen  is  membranous  and  connected  directly  with  the  laba- 
coria  and  cervacoria  (cc). 

Precoila. — The  strongly  chitinized  acetabulum  located  near  the 
ventro-mesal  angle  of  the  vertex  or  the  dorso-lateral  angle  of  the  clypeus 
is  the  precoila  (pr).  The  preartis  of  the  mandible  (py)  articulates  at  this 
point.    The  precoila  is  distinct  in  all  Tenthredinoidea. 

Mandibularia. — The  small  transverse  whitish  or  light-colored  area 
ventrad  of  the  ventral  margin  of  the  head  on  the  cephalo-lateral  aspect  is 
the  mandibularia  (mb).  It  is  usually  only  slightly  chitinized  and  merges 
with  the  mandacoria  without  any  indication  of  a  suture.  The  extensacuta 
(ec)  of  the  extensatendon  of  the  mandible  is  usually  distinct.  The  mandi- 
bulariae  are  sometimes  very  large,  as  in  the  Xyelidae  (Fig.  27). 

Postcoila. — The  cup-shaped  acetabulum  on  the  latero-ventral  angle 
of  the  postgena  and  caudal  angle  of  the  mandibularia  is  the  postcoila 


337]  LARVAE  OF  THE  TENTH REDINOIDEA-rYV ASA  19 

{pit),  where  the  postartis  of  the  mandible  articulates.  The  occipital  suture 
(os)  when  present  originates  in  or  near  the  postcoila.  The  postcoila  is 
always  present.  

Paracoila. — There  is  a  slight  projection  at  the  mesal  end  of  the  caudo- 
ventral  margin  of  the  head  where  the  cardo  of  the  maxilla  articulates.  This 
is  the  paracoila  (pi).  It  is  not  well  developed  but  is  present  and  discernible 
in  nearly  all  tenthredinid  larvae.  . 

Odontoidea. — The  lateral  cervical  sclerite  is  articulated  with  the  head 
capsule  on  the  mesal  margin  of  the  postgena  some  distance  ventrad  of  the 
origin  of  the  vertical  furrow.  This  point  of  articulation  is  an  odontoidea 
(od)  and  is  rather  indistinct  in  the  larvae  of  this  group  of  insects. 

Tentorium— -The  tentorium  is  very  simple  in  tenthredinid  larvae. 
It  consists  of  the  metatentoria  (m/),  corpo tentorium  (ci),  and  pretentoria. 
The  supratentoria  are  apparently  obsolete.  The  metatentorium  is  the 
strongly  chitinized  conspicuous  ental  bar  extending  into  the  head  capsule 
from  the  ventro-mesal  margin  of  each  postgena.  The  two  metatentoria 
fuse  on  the  meson  and  form  the  bridge,  the  corpotentorium,  which  gives 
support  to  the  caudo- ventral  portion  of  the  head.  The  position  of  each 
metatentorina  is  indicated  by  a  pit-  or  slit-like  depression  (mn).  The  loca- 
tion of  the  pretentorinae  (pn)  has  already  been  indicated.  A  strong 
ental  arm,  much  smaller  than  a  metatentorium,  extends  yentro-mesad 
from  each  pretentoria  into  the  head  capsule  and  fuses  with  the  corpoten- 
torium near  the  middle  of  the  latter.  This  bar  is  a  pretentorium.  In 
ecdysis  the  tentorium  breaks  in  the  middle  of  the  corpotentorium,  freeing 
the  mesal  ends  of  the  pretentoria  and  metatentoria.  The  tentorium  in 
the  Xyelidae  and  Pamphiliidae  is  similar  to  that  of  the  Tenthredinidae  in 
structure  and  location. 

The  movable  parts  of  the  head  include  all  the  appendages,  that  is,  the 
antennae,  mandibles,  maxillae,  and  labium. 

Antennae. — The  antennae  are  present  in  the  larvae  of  all  Tenthredin- 
oidea,  but  their  structure,  size,  position,  and  number  of  segments  vary  in 
the  different  families  and  subfamilies.  Each  is  borne  by  a  distinct  anten- 
naria  (ar)  which  is  located  in  the  ventrolateral  portion  of  the  vertex;  in  the 
generalized  families  they  are  located  cephalad  of  the  ocularia;  in  the 
specialized,  ventrad  of  them.  The  antennariae  are  usually  subcircular  or 
subquadrate.  The  antacoria  (an)  is  usually  extensive,  distinctly  convex, 
and  whitish  in  color  (Figs.  143-153).  It  is  only  occasionally  narrow  and 
confined  to  the  periphery  of  the  antennaria,  as  in  certain  Nematinae 
(Fig.  154).  The  antennae  of  the  Pamphiliidae  (Fig.  26)  are  setiform, 
one-half  as  long  as  the  head  is  wide,  with  seven  cylindrical  segments. 
There  is  a  circular  sensorium  on  the  ventral  aspect,  of  the  distal  portion  of 
the  second,  third,  and  fifth  segments  (Fig.  39).  In  the  Xyelidae  (Fig.  27)  ' 
the  segments  are  shorter  but  thicker,  and  vary  in  number  from  six  to  seven 


20  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [338 

according  to  the  genus.  The  antennae  of  the  Tenthredinidae  (Figs- 
145,  147,  149,  150,  153)  apparently  represent  a  specialization  from  those  of 
the  Xyelidae.  They  are  much  shorter  and  vary  in  number  of  segments 
from  one  to  five.  The  antennae  vary  in  shape  and  are  conical  in  the 
Emphytinae  and  other  generalized  subfamilies,  with  five  ring-like  or 
limpet-shaped  segments,  with  four  more  or  less  irregular,  incomplete,  often 
partly  fused  segments  in  the  Nematinae  (Fig.  145),  or  flattened  and  fused 
into  a  single  segment  in  the  Schizocerinae  or  button-like  and  one-segmented 
in  the  Cimbicinae,  Fenusinae,  and  Metallus  (Fig.  147),  or  subconical  or 
irregular  as  in  some  Nematinae  and  Phlebatrophia  (Fig.  150).  When 
the  antennae  consist  of  five  segments,  they  are  usually  cylindro-conical 
and  remarkably  uniform  in  shape.  The  antennal  segments  are  usually 
strongly  chitinized,  more  or  less  ring-like,  successively  smaller  in  diameter, 
and  the  distal  segment  is  conical  or  occasionally  erect  and  peg-like  as  in  the 
Diprioninae.  The  segments  do  not  always  form  a  complete  ring;  one 
side  may  be  reduced  to  a  mere  line,  or  be  entirely  wanting  as  in  some 
Nematinae,  in  which  cases  the  segment  is  said  to  be  incomplete.  Some- 
times fusion  of  all  or  some  of  the  segments  may  take  place.  Certain 
segments  are  sometimes  setiferous  and  also  bear  some  sensoria.  The 
number  of  segments  is  constant  for  a  subfamily.  The  relative  length  and 
shape  of  the  segments  vary,  but  are  constant  in  species  in  some  cases,  and 
in  others  constant  in  genera.  The  antennae  of  the  Cephidae  are  small, 
with  four  or  five  segments,  while  in  the  Xiphydriidae  they  are  three- 
segmented  and  in  the  Siricidae  and  Oryssidae  single-segmented.  It  is 
possible,  therefore,  to  arrange  the  families  of  Tenthredinoidea  in  an  as- 
cending series  according  to  the  number  and  size  of  the  segments  of  the 
antennae.  The  tenacity  of  the  antennae  is  well  illustrated  in  the  Oryssidae, 
which  in  spite  of  the  extreme  modification  of  other  structures  still  retains 
one-segmented  antennae. 

Mouth-parts. — The  larvae  of  the  Tenthredinoidea  possess  well-devel- 
oped mandibulate  mouth-parts.  They  include  the  mandibles,  maxillae, 
and  labium,  and  are  remarkably  uniform  and  constant  in  structure  in  the 
different  families.  The  modifications  take  place  in  the  relative  size  of 
parts  and  in  the  number  of  segments  of  the  articulated  parts. 

Mandibles. — The  mandibles  (md)  are  always  present,  and  are  typically 
thick,  strongly  chitinized,  and  sharply  dentate,  the  dextral  dissimilar  to 
the  sinistral  in  the  number  and  shape  of  the  dentes,  and  in  having  one  or 
two  and  occasionally  more  mandibular  setae  on  the  lateral  aspect.  The 
number  and  arrangement  of  the  dentes,  the  number  of  mandibular  setae, 
and  the  relative  size  and  shape  of  the  mandibles  are  constant  for  certain 
genera.  The  mandibles  of  the  Schizocerinae  are  rather  thin  and  flattened, 
and  in  Phlebatrophia  very  thin  and  elongated  with  one  triangular  blade- 


339]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  21 

like  dentis.  In  this  character  the  larvae  of  this  genus  are  more  specialized 
than  all  other  larvae,  even  including  Oryssus. 

Maxillae. — The  maxillae  (tnx)  are  always  present  and  typically  consist 
of  cardo,  stipes,  subgalea,  palpifer,  palpus  (mp),  galea  (gl),  and  lacinia 
(la).  The  cardo  is  usually  more  or  less  chitinized  and  is  divided  into  a  small 
subcardo  and  a  larger  triangular  alacardo.  The  subcardo  articulates  with 
the  head  in  the  paracoila.  On  the  lateral  margin  of  the  alacardo  the  large 
stipes  is  attached.  The  stipes  is  usually  less  chitinized  than  the  cardo, 
submenbranous,  convex  on  the  lateral  aspect,  and  attached  to  the  lateral 
margin  of  the  alacardo.  The  cephalic  aspect  is  membranous  and  is  con- 
tinuous with  the  maxacoria.  The  caudal  aspect  along  the  mesal  margin 
is  strongly  chitinized  and  continuous  with  the  elongate  triangular  subgalea. 
The  line  of  fusion  is  indicated  by  a  distinct  oblique  chitinized  ridge  which 
extends  from  near  the  proximal  end  of  the  subgalea  to  the  lateral  angle  of 
the  lacinia.  The  latero-ventral  angle  of  the  stipes  is  often  produced  as  a 
small  triangular  lobe,  the  stipal  angle  of  Crampton  (1921)  as  in  the 
Tenthredininae.  The  palpifer  is  a  more  or  less  membranous,  mound-like 
lobe  attached  to  the  distal  end  of  the  cephalic  margin  of  the  stipes  and 
often  bears  one  or  more  setae.  The  palpus  is  borne  by  the  palpifer  and 
typically  consists  of  four  more  or  less  conical  segments.  The  relative 
size  and  shape  of  the  segments  vary  and  afford  good  characters  for  the 
separation  of  genera  and  species.  The  galea  is  typically  strongly  chitinized, 
digit-like,  conical  or  slightly  curved  mesad,  bluntly  pointed,  unsegmented, 
and  usually  smaller  than  the  palpus.  The  lacinia  is  located  mesad  of  the 
galea  and  cephalo-ventrad  of  the  subgalea.  It  is  usually  subtriangular, 
slightly  flattened,  lobe-like,  and  bears  a  row  of  setae  on  its  oblique  mesal 
margin.  It  is  sometimes  distinctly  flattened,  strongly  chitinized,  with  a 
stiff  row  of  setae,  as  in  the  Emphytinae,  or  rounded  and  with  minute  spi- 
nous setae  as  in  Diprion,  or  with  a  sharp  triangular  compressed  seta  in 
addition  to  an  ordinary  row  of  setae  as  in  the  Xyelidae.  The  galea  and 
lacinia  are  always  present  except  in  Oryssus  but  are  reduced  in  size  in 
Tremex.  It  is  interesting  to  note  that  in  the  leaf-miners  the  palpi  are 
reduced  but  the  galea  are  usually  normal  in  size  and  larger  than  the  palpi. 
In  Oryssus  the  maxillae  are  fleshy  lobes  with  all  the  component  parts 
obsolete  and  with  a  brownish  area  in  which  a  few  sensory  papillae  are  lo- 
cated (Rohwer  and  Cushman,  1917).  The  palpi  are  apparently  two- 
segmented  in  the  Xiphydriidae  and  Siricidae. 

Labium. — The  labium  (li)  consists  typically  of  submentum,  mentum, 
stipulae,  palpiger,  palpi  (Ip),  and  togaglossa — representing  the  fused 
glossae  and  paraglossae.  The  submentum  (sm)  and  mentum  (w)  is  typ- 
ically membranous,  convex,  with  two  or  more  setae,  and  very  broad  in 
the  larvae  of  most  species.  In  some  cases,  as  in  the  Diprioninae,  part 
of  the  mentum  is  chitinized.      In  the  leaf-miners,  such  as  Fenusa,  Metallus. 


22  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (340 

and  Phlebatrophia,  the  rrientum  is  strongly  chitinized  and  flattened. 
There  is  a  distinct  median  longitudinal  depression  in  Metallus.  The 
palpiger  is  practically  wanting.  The  palpus  is  typically  three-segmented 
(Fig.  157).  The  relative  size  and  structure  of  the  segments  vary,  but  are 
usually  constant  for  a  subfamily  or  a  genus.  In  Tremex  and  Phlebatrophia 
the  palpi  are  apparently  two-segmented  and  very  minute,  while  in  Oryssus 
they  are  obsolete.  The  stipulae  are  typically  membranous,  broad,  some- 
times bearing  two  setae,  and  fused  with  the  mentum  without  any  indication 
of  a  suture.  The  stipulae  are  flattened  and  chitinized  in  Metallus  and  the 
Fenusinae.  Totaglossa  is  typically  membranous,  subglobose  or  bluntly 
pointed,  fused  with  the  stipulae  without  any  indication  of  a  suture.  It  is 
readily  identified  on  account  of  its  median  position  and  characteristic 
shape  and  structure.  There  is  a  slit-like  opening  for  the  duct  of  the  silk- 
gland,  the  sericos  (crv)  on  the  meson  near  the  caudo-ventral  aspect  of  the 
totaglossa.  The  shape,  size,  and  location  of  the  sericos  vary  but  it  is 
always  present  and  chitinized.  The  cephalic  or  dorsal  aspect  of  the 
totaglossa  is  strongly  convex,  membranous,  and  sometimes  bears  a  few 
minute  setae  and  sensoria. 

Prepharynx. — The  prepharynx,  the  so-called  "hypopharynx"  of  the 
larvae  of  the  Tenthredinoidea,  is  very  simple  in  structure  and  the  bound- 
aries of  the  parts  that  can  be  identified  in  generalized  insects  (Yuasa, 
1920)  are  obsolete.  The  propharynx  consists  of  the  epipharynx  and  epi- 
gusta.  The  epipharynx  is  membranous,  is  of  the  same  size  and  shape  as  the 
labrum,  and  bears  an  oblique  row  of  a  few  setae  on  each  side  slightly 
dorsad  of  the  ventral  margin.  The  epigusta  is  membranous  and  is  sup- 
ported on  each  lateral  portion  by  a  torma.  The  ambipharynx  is  restricted 
and  membranous.  The  parapharynx  consists  of  the  basipharynx  and 
hypopharynx  (hx).  The  basipharynx  is  subglobose  or  convex,  often 
slightly  chitinized  on  the  sides,  sometimes  having  a  few  minute  setae, 
and  usually  converges  ventrad.  The  portion  ventrad  of  the  constriction  is 
considered  as  belonging  to  the  hypopharynx,  but  is  usually  membranous 
and  continuous  with  the  Cephalic  surface  of  the  totaglossa  without  any 
indication  of  differentiation.  The  laciniae  fit  against  the  sides  of  the 
constricted  part  Of  the  parapharynx.  No  striking  modification  in  form  of 
the  prepharynx  appears  in  the  different  families. 

Trunk. — The  portion  of  the  body  caudad  of  the  head  is  the  trunk. 
It  consists  of  thirteen  segments  which  connect  with  the  head  by  means  of 
the  cervacoria.  The  first  three  segments  compose  the  thorax  and  the 
remainder  the  abdomen. 

Cervacoria. — The  membrane  (cc)  which  connects  the  thorax  with  the 
head  is  rather  broad  and  usually  folded  under  the  protruding  cephalic  end 
of  the  prothorax.  There  is  a  chitinized  sclerite  on  each  side,  the  cephalic 
end  of  which  articulates  with  the  head  against  the  odontoidea  and  the 


341]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  23 

caudal  end  with  the  epimeron  and  coxa.  This  is  the  lateral  cervical  sclerite 
(les),  which  is  always  present  and  usually  distinctly  colored — brownish  or 
blackish.  The  cervacoria  is  continuous  with  the  submentum  on  the 
ventral  aspect,  and  is  often  produced  on  the  meson  as  a  small  mound-like 
setiferous  protuberance,  as  in  Strongylogaster. 

Thorax. — The  prothorax  is  usually  constricted  on  the  cephalic  portion, 
the  dorsal  aspect  is  declivous,  and  the  lateral  aspect  is  produced.  The 
dorsum  is  typically  divided  into  a  narrow  cephalic  portion  and  a  wide 
caudal  one,  which  in  turn  may  be  subdivided  into  two  or  more  annulets 
(Fig.  65).  The  first  division  is  usually  setiferous  on  the  lateral  aspect, 
while  the  second  division  is  setiferous  on  the  dorsal  aspect.  On  the  middle 
of  the  lateral  aspect  there  is  a  large  spiracle.  This  is  the  mesospiracle 
(msp),  which  has  migrated  onto  the  prothorax.  There  is  another  setiferous 
area  cephalo-ventrad  of  the  spiracle.  The  prothoracic  leg  is  attached  to 
the  latero-ventral  margin  of  the  segment,  ventrad  of  the  setiferous  sub- 
spiracular  area,  which  is  usually  produced  as  a  lobe  and  which  Crampton 
(1918)  has  designated  as  the  surcoxal  plate.  There  is  a  small,  usually 
strongly  chitinized  sclerite  cephalad  of  the  leg.  This  is  the  episternum- 
epimeron,  or  the  eupleuron  of  Crampton.  The  dorsal  aspect  of  the  pro- 
thorax and  often  the  lateral  one  may  be  chitinized  and  colored,  forming 
shield-like  areas  as  in  the  Xyelidae  and  certain  leaf-miners.  The  proster- 
num  is  usually  membranous,  subdivided  into  two  or  more  annulets,  but 
sometimes  it  is  flattened  and  strongly  chitinized  as  in  Metallus.  There  is 
usually  a  small  pit  or  chitinized  rod  near  the  caudal  part  of  the  segment  on 
the  ventral  aspect.  This  is  the  profurcellina  (Pfn)  and  marks  the  caudal 
limit  of  the  prosternum.  The  meso thorax  and  metathorax  are  more 
or  less  similar  in  structure,  frequently  the  largest  segments  in  the  body, 
more  or  less  ring-like  and  often  distinctly  annulate.  The  metaspiracles 
(tsp)  are  located  in  the  metacoria  and  are  usually  minute  and  functionless. 
The  mesothorax  and  metathorax  resemble  the  prothorax  in  other  details. 
In  the  Fenusinae  (Fig.  21)  and  Metallus  (Fig.  22)  the  dorsum  of  the 
mesothorax  and  metathorax  is  provided  with  an  ovoid,  fleshy,  sucker-like, 
low  protuberance  (scp)  on  each  side  of  the  meson.  Its  function  is  not 
known.  Dimorphopteryx  is  characterized  by  the  presence  of  a  pair  of 
prominent  dorsal  protuberances  on  the  prothorax  and  a  median  protu- 
berance on  the  mesothorax. 

Thoracic  Legs. — The  larvae  of  the  Tenthredinoidea,  with  the  exception 
of  the  Oryssidae,  possess  three  pairs  of  thoracic  legs.  They  are  the  most 
persistent  of  all  the  thoracic  and  abdominal  appendages  and  as  a  rule  are 
very  similar  in  structure,  both  facts  indicating  a  common  origin.  A  typical 
leg  consists  of  five  more  or  less  well-chitinized  segments:  coxa,  trochanter, 
femur,  tibia,  and  a  distal  segment  representing  the  fused  tarsus  and  tarsal 
claw. 


24  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [342 

The  coxa  (ex)  is  usually  the  largest  of  all  the  segments,  subconical,  and 
articulated  to  the  ventro-lateral  margin  of  the  segment.  The  cephalo- 
dorsal  angle  is  strongly  chitinized  and  articulates  against  the  chitinized 
end  of  the  episternum-epimeron.  There  is  a  distinct  oblique  depression 
extending  from  this  angle  to  the  middle  of  the  dorso-distal  margin  of  the 
coxa.  The  distal  ends  of  the  coxae  are  usually  chitinized  and  form  ring- 
like thickenings.  The  ventral  half  of  the  coxa  is  more  or  less  mem- 
branous. The  trochanter  (tr)  is  usually  small,  longer  on  the  ventral 
than  on  the  dorsal  aspect.  The  femur  (fin)  is  usually  cylindrical  and  is 
often  dilated  at  the  distal  end.  Its  ventro-distal  portion  is  usually  mem- 
branous and  is  sometimes  produced,  forming  a  pointed  projection,  the 
femoral  process  (//>),  as  in  Dolerinae  (Fig.  135)  and  in  related  subfamilies. 
The  tibia  (/)  is  subcylindrical,  narrower  in  diameter  at  the  distal  than  at  the 
proximal  end,  and  either  longer  or  shorter,  than  the  femur  or  subequal  to  it. 
The  distal  segment  is  typically  very  short  and  claw-like.  The  apparent 
claw  (cw)  represents  a  fusion  of  the  tarsus  and  tarsal  claw,  and  is  usually 
sharp  and  distinctly  curved.  The  segments  are  usually  setiferous  and 
more  or  less  membranous  on  the  ventral  aspect  and  at  the  joints. 

The  general  plan  of  structure  of  the  legs  is  the  same  in  a  majority 
of  the  larvae,  but  there  are  variations  in  the  shape,  size,  arrangement  of 
setae,  and  in  the  number  of  apparent  segments  within  the  families  and 
subfamilies.  The  variations  usually  consist  in  the  suppression  of  the 
trochanter  as  in  Phlebatrophia  (Fig.  136)  and  the  Fenusinae  (Fig.  140), 
or  in  the  modification  of  the  distal  segment  as  in  the  Pamphiliidae  (Fig.  130) 
and  Hylotominae,  or  in  the  reduction  of  the  entire  structure  to  a  fleshy, 
subconical,  indistinctly  segmented  clawless  protuberance  as  in  Phleba- 
trophia and  certain  highly  specialized  families.  The  absolute  homology  of 
the  segments  in  a  modified  leg  can  not  be  established,  but  when  the  number 
of  the  segments  is  less  than  five  it  is  probable  that  the  trochanter  is  the 
first  one  to  disappear. 

The  Pamphiliidae  are  distinct  from  all  other  tenthredinoid  larvae  in 
having  setaceous  legs  with  all  segments  cylindrical  except  the  distal  ones. 
The  distal  segment  is  very  slender,  non-setiferous,  straight,  and  sharply 
pointed  without  indication  of  a  claw.  The  Xyelidae  (Fig.  131)  possess 
legs  which  are  small  but  typical  in  structure  and  number  of  segments. 
It  is  quite  possible  to  derive  the  normal  tenthredinid  legs  from  those  of  the 
Xyelidae.  In  the  subfamilies  of  the  Tenthredinidae,  a  series  of  modifica- 
tions of  the  legs  is  found,  altho  the  majority  of  the  subfamilies  and  genera 
are  provided  with  typical  five-segmented,  well-developed  claw-bearing 
legs.  The  Phyllotominae  (Figs.  141,  142)  are  characterized  by  very 
short,  stubby,  chitinized  legs  which  consist  of  four  segments,  including  the 
large  strongly  curved  claw.  Phlebatrophia  (Fig.  136)  is  unique  among  the 
Tenthredinidae  in  having  fleshy,  rudimentary  clawless  legs.    The  Fenusi- 


343]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  25 

nae  (Fig.  140)  also  possess  small  four-segmented  legs  but,  unlike  the 
Phyllotominae,  have  simple  and  ring-like  segments  and  claws  normal  in 
form.  The  Hylotominae  differ  from  the  other  subfamilies  in  possessing 
apparently  six-segmented  legs.  Their  distal  portion  consists  of  a  distinctly 
separated  tarsus  and  claw  and  bears  an  empodium-like  fleshy  lobe  on  the 
caudal  portion  of  the  claw.  The  minimum  number  of  segments  is  found  in 
the  legs  of  the  Schizocerinae  (Fig.  139),  where  the  mesothoracic  and 
metathoracic  legs  consist  of  only  three  simple  cylindrical  segments,  while 
the  prothoracic  legs  are  composed  of  four.  There  is  a  well-developed 
fleshy  subglobose  lobe  caudad  of  the  claw.  It  is  interesting  to  note  that 
the  gall-makers,  for  example,  Pontania  have  essentially  the  same  type  of 
legs  as  the  leaf-feeding  Nematinae  (Fig.  133),  while  the  leaf-mining  larvae 
of  the  Fenusinae,  Schizocerinae,  and  others,  have  modified  legs.  The 
highly  specialized  families,  Cephidae,  Xiphydriidae,  and  Siricidae,  possess 
fleshy,  indistinctly  segmented  rudimentary  legs  which  are  never  provided 
with  claws.  The  most  specialized  family,  Oryssidae,  is  entirely  apodous. 
The  legs  present,  therefore,  very  good  characters  for  differentiating  the 
families  and  the  subfamilies  of  the  Tenthredinoidea.  The  phylogenetic 
significance  of  the  thoracic  legs  is  quite  evident. 

Abdomen. — The  segments  composing  the  abdomen,  with  the  exception 
of  the  two  caudal  segments,  are  more  or  less  similar  in  structure,  ring-like, 
and  usually  subdivided  into  four  to  seven  annulets.  Segments  2-7  or  2-8 
and  10  usually  bear  a  pair  of  larvapods,  the  so-called  "prolegs,"  on  the 
ventral  aspect.  The  first  and  ninth  abdominal  segments  never  possess 
larvapods  except  in  the  Xyelidae.  The  third  abdominal  segment  is  more 
typical  than  the  other  segments  and  least  modified,  and  for  this  reason 
has  been  used  as  a  type  for  description.  In  a  typical  larva  this  segment  is 
subdivided  into  a  number  of  annulets  on  the  dorsum  and  latus  dorsad  of 
the  spiracular  line.  The  latus  ventrad  of  the  spiracular  line  is  typically 
lobe-like,  setiferous,  and  distinguishable  as  two  areas,  the  subspiracular 
area  (ssl)  or  the  surpedal  area  (sdl)  according  to  the  location.  When 
these  areas  are  distinctly  lobe-like  they  are  designated  as  subspiracular 
lobe  and  surpedal  lobe.  The  latter  corresponds  to  the  thoracic  surcoxal 
plate  of  Crampton.  The  subspiracular  and  surpedol  lobes  sometimes  fuse 
and  extend  the  full  length  of  the  segment  as  an  oblique  fold,  as  in  wood- 
boring  larvae  and  the  Hylotominae.  In  the  latter  this  lobe  is  conspicuously 
produced  laterad,  making  the  segment  distinctly  flattened.  The  sub- 
spiracular and  surpedal  lobes,  when  fused,  are  known  as  the  sublateral 
lobe  (sll).  The  larvapods  are  located  on  the  ventral  aspect  some  distance 
from  the  meson.  The  sternum  is  divided  into  two  or  more  annulets,  the 
annulation  being  usually  distinct  but  its  exact  limits  difficult  to  determine 
on  account  of  the  presence  of  the  larvapods.  The  intersegmental  coria 
(cor)  is  distinctly  indicated  on  the  venter  (Fig.  81).     The  segmentation 


26  ILLINOIS  BIOLOGICAL  MONOGRAPHS      "  {344 

is  distinct  but  the  limits  of  the  somites  are  not  so  readily  determined.  The 
cephalic  limit  of  a  segment  is  usually  indicated  by  the  distinct  depression 
on  the  dorsal  and  lateral  aspects  and  by  the  short  ventro-lateral  depressions 
which  terminates  at  the  cephalic  end  of  the  subspiracular  lobe.  Thus 
the  cephalic  limit  of  a  segment  is  not  a  straight  line,  but  curves  caudo- 
ventrad  and  then  slightly  cephalo-ventrad  of  the  subspiracular  lobe. 
The  typical  annulation  and  arrangement  of  setae,  tubercles,  and  glandubae 
on  the  typical  abdominal  segment  are  indicated  elsewhere  (Figs.  73-79). 
The  ninth  abdominal  segment  is  readily  distinguishable  because  of  its 
location  and  shape,  and  by  the  absence  of  spiracles  and  larvapods.  It  is 
typically  smaller  than  the  preceding  segments,  tapers  more  or  less  caudad, 
and  usually  has  one  less  annulet  on  the  dorsum  than  have  the  preceding 
segments.  Its  caudal  limit  is  usually  distinctly  indicated  by  a  deep 
depression.  The  tenth,  or  the  apparent  ultimate,  segment  is  modified  and 
differs  from  the  other  abdominal  segments  because  of  the  presence  of  the 
anus,  anal  larvapods,  and  other  structures  peculiar  to  this  segment  (Figs. 
89-103). 

Tenth  Urotergum. — The  tergum  of  the  tenth  abdominal  segment  is 
usually  convex  and  often  setiferous.  It  sometimes  bears  numerous  spinous 
processes,  as  in  the  Blennocampinae  and  Dimorphopteryx,  or  paired  suranal 
protuberances  as  in  certain  genera  of  Nematinae,  or  a  median  suranal 
process  (srp),  as  in  the  Cephidae  and  its  allies.  In  these  highly  specialized 
families  the  tenth  abdominal  segment  is  produced  cephalad  and  fits  into 
the  deep  semicircular  emargination  of  the  ninth  segment.  The  tergum 
possesses  a  distinct,  deep,  median  longitudinal  depression  extending 
from  the  cephalic  end  of  the  tergum  to  the  proximal  end  of  the  median 
suranal  process.  In  the  Xyelidae  the  tergum  is  produced  distinctly  hunch- 
like on  the  meson  of  the  cephalic  third  caudad  of  the  deep,  broad  transverse 
depression.  The  tergum  is  produced  caudad  in  certain  species  of  Pachy- 
nematus  and  forms  a  distinct  caudal  projection.  In  this  genus  the  gland- 
ubae are  very  conspicuous.  The  size,  convexity,  number,  and  arrangement 
of  the  spinous  protuberances,  caudal  processes,  and  setae  are  useful 
characters  in  recognizing  different  subfamilies  and  genera. 

Suranal  Lobe. — The  membranous  lobe  (srl)  of  the  Tenthredinidae, 
which  forms  the  dorsal  wall  of  the  anal  slit  may  represent  the  rudiment  of 
the  dorsal  half  of  the  ultimate  segment,  the  so-called  "telson."  It  bears 
numerous  setae  of  varying  size  and  number  and  is  usually  fused  with  the 
tergum  of  the  tenth  segment.  In  the  larvae  of  the  Xiphydriidae  and  its 
allies,  which  possess  a  median  suranal  process,  the  suranal  lobe  is  distinct, 
more  or  less  chitinized  in  part,  usually  separated  from  the  tenth  tergum  by 
a  ridge  or  by  an  oblique  suture  which  extends  from  the  chitinized  depres- 
sion dorsad  of  the  suranal  process  to  the  lateral  end  of  the  anal  slit  (au). 
The  area  cephalad  of  this  oblique  suture  is  the  pleuron  of  the  tenth  seg- 
ment. 


345]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  27 

Subanal  Lobe. — The  membranous  lobe  (sbl)  which  forms  the  ventral 
wall  of  the  anal  slit  may  represent  the  rudiment  of  the  ventral  half  of  the 
ultimate  segment  or  "telson."  It  is  never  distinctly  chitinized,  always 
indistinguishably  fused  with  the  tenth  abdominal  sternum,  usually  setifer- 
ous,  and  is  rather  restricted  in  extent.  In  the  Tenthredinidae  the  subanal 
lobe  is  strongly  convex  and  extends  to  the  anal  larvapods,  the  postpedes  of 
Crampton.  If  the  subanal  lobe  represents  a  part  of  the  telson,  and  if  the 
subanal  appendages  (sba)  of  the  Pamphiliidae  and  Cephidae  are  the 
appendages  of  the  ultimate  segment,  then  the  subanal  lobe  possesses  a 
pair  of  genuine  appendages.  In  the  larvae  of  the  Xyelidae  there  occur 
sometimes  distinct  subglobose  setiferous  swellings  dorso-caudad  of  the  anal 
larvapods.    Their  homology  and  function  are  unknown. 

Tenth  Urosternum. — The  sternum  of  the  tenth  abdominal  segment  is 
restricted  in  extent,  more  or  less  convex,  and  often  glabrous.  In  the 
Xyelidae  and  Tenthredinidae  the  anal  larvapods  occupy  the  greater  part 
of  the  caudal  portion,  which  is  thereby  produced  subconically  ventrad. 
This  sternum  is  usually  glabrous  and  more  or  less  flattened  in  apodous 
larvae.    There  are  no  annulations  observable  on  this  sternum. 

Suranal  Process. — In  boring  larvae,  the  ultimate  segment  is  provided 
with  a  strongly  chitinized  mesal  suranal  process  (srp)  on  the  suranal  lobe. 
This  process,  which  has  been  variously  designated  by  different  writers,  is 
characteristic  of  the  families  Cephidae  (Figs.  108,  109,  112,  114,  115) 
Xiphydriidae  (Figs.  107,  110),  and  Siricidae  (Figs.  113,  120,  122).  The 
size,  shape,  number,  and  arrangement  of  the  dentiform  tubercles  and 
setae  vary  in  different  families  but  they  are  constant  within  species  and 
often  also  within  genera.  It  is  undoubtedly  an  adaptive  structure  devel- 
oped in  connection  with  the  boring  habit  of  the  larvae.  It  is  interesting  to 
note  that  in  some  of  the  gall-making  larvae  of  Pontania  and  leaf-stem 
boring  larvae  of  Caulocampus,  the  tergum  of  the  ultimate  segment  is 
produced  on  the  caudo-meson  and  forms  a  distinct  protuberance  provided 
with  chitinized  points  on  its  caudal  end.  The  larvae  of  the  Pamphiliidae 
also  possess  a  minute  hook-like  process  on  the  caudo-meson  of  the  ultimate 
tergum.  The  genetic  connection  of  this  hook-like  tubercle  and  the  distinct 
suranal  process  of  highly  specialized  families  is  doubtful,  but  it  is  not  difficult 
to  surmise  a  common  origin  for  the  suranal  process  of  the  Cephidae, 
Xiphydriidae,  and  Siricidae.  The  suranal  process  corresponds  to  the 
postcornu  of  Crampton. 

Caudal  Protuberances. — In  certain  genera  of  the  Nematinae  and  in 
a  few  other  genera  of  the  Tenthredinidae,  the  tergum  of  the  ultimate 
segment  is  provided  with  two  or  more  protuberances  which  vary  in  size, 
shape,  number,  and  position  in  different  genera.  A  typical  condition  in 
nematid  larvae  is  found  in  Pteronidea  (Figs.  126,  127),  which  possess  a 
pair  of  conical,  pointed,  well-chintinized  processes  (srp),  one  on  each  side, 


2S  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [346 

on  the  caudal  margin  of  the  tergum  dorsad  of  the  membranous  suranal 
lobe.  These  processes  are  always  two  in  number  and  more  or  less  constant 
in  position  in  nematid  larvae,  but  vary  in  size  and  shape  altho  constant 
within  species.  They  are  conical,  subconical,  sharply  or  bluntly  pointed, 
truncate,  or  distinctly  swollen  at  the  distal  end  as  in  Pteronidea  trilineata. 
The  tenth  abdominal  tergum  of  the  spinous  larvae  of  the  Blennocampinae 
is  provided  with  several  symmetrically  arranged  conspicuous  spinous 
processes  on  the  caudal  portion  and  in  part  along  the  caudal  margin.  The 
larva  of  Dimorphopteryx  is  unique  among  the  Emphytinae  in  the  possession 
of  four  very  distinct,  sharply  pointed  spinous  protuberances  along  the 
caudal  margin  of  the  ultimate  segment  dorsad  of  the  suranal  lobe.  In 
certain  of  the  gall-making  species  of  Pontania  the  caudal  end  of  the  tenth 
abdominal  tergum  is  produced  caudad  and  forms  a  median  prominence 
which  usually  has  two  minute  strongly  chitinized  points  close  together  on 
the  meson.  A  similar  protuberance  is  found  in  the  larvae  of  Caulocampus 
acericaulis.  In  the  Siricidae  a  pair  of  minute  sharply  pointed  solid  chitin- 
ized spines  occurs  on  the  tergum  of  the  ultimate  segment,  one  on  each 
side  of  the  median  longitudinal  depression  (Fig.  113). 

These  protuberances  have  been  variously  designated.  Crampton 
(1919)  considers  the  paired  protuberances  and  spines  to  be  homologous 
with  the  cerci  of  Orthoptera  and  Ephemeridae.  If  they  represent  rudi- 
mentary cerci  they  must  belong  to  the  eleventh  abdominal  segment, 
the  telson  of  embryologists,  since  the  true  appendages  of  the  tenth  segment 
are  transformed  into  the  anal  larvapods.  But  this  homology  is  open  to 
question  because  these  protuberances  are  mere  projections  of  the  surface 
and  not  at  all  appendages  in  a  morphological  sense,  and,  furthermore, 
because  in  other  larvae  the  number  and  position  of  the  protuberances  vary 
considerably.  No  one  would  suggest  that  the  caudal  tubercles  and  spinous 
processes  of  Dimorphopteryx,  Blennocampa,  Hypergyricus,  Caulocampus, 
and  others  are  homologous  with  the  cerci  of  generalized  insects;  yet,  there 
is  no  reason  to  assume  that  the  caudal  tubercles  of  these  larvae  are  differ- 
ent in  origin,  structure,  and  function — whatever  that  may  be — from  the 
suranal  paired  processes  of  the  nematid  larvae.  These  protuberances 
may  or  may  not  be  at  all  related  genetically  to  the  suranal  median  process 
of  the  Cephidae  and  its  allies.  At  any  rate  our  present  knowledge  does 
not  permit  any  definite  conclusion  regarding  the  true  nature  or  homology 
of  these  structures.  The  interpretation  advanced  by  Middleton  (1921) 
seems  more  reasonable.    He  named  these  protuberances  pseudocerci. 

Subanal  Appendages. — The  larvae  of  the  Pamphiliidae  (Figs.  91,  95) 
and  Cephidae  (Figs.  108,  109,  111,  116,  117,  118,  119)  possess  a  pair  of 
subanal  appendages  on  the  ultimate  segment,  one  on  each  side  ventrad 
of  the  lateral  ends  of  the  anal  slit.  These  appendages  are  long,  setaceous, 
and  three-segmented  in  the  Pamphiliidae,  but  are  rudimentary,  papilliform, 


347)  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  29 

and  only  indistinctly  segmented  in  the  Cephidae.  When  the  appendages 
are  long  and  setiform,  the  relative  length  and  color  of  the  segments  differ 
in  different  species.  In  the  Cephidae  the  appendages  may  or  may  not  be 
provided  with  accompanying  setae  near  the  proximal  end,  and  these 
setae  may  or  may  not  form  a  continuous  group  with  the  setae  on  the 
sternum. 

That  these  structures  are  true  appendages  of  the  segment  is  indicated 
by  the  segmentation  and  by  the  fact  that  they  are  invariably  articulated 
at  the  proximal  end  against  the  surface,  not  being  mere  protuberances 
like  the  caudal  processes  of  the  tergum.  Some  embryologists  consider  these 
appendages  to  be  homologous  with  the  cerci  of  generalized  insects  and  the 
anal  "prolegs"  of  lepidopterous  larvae,  and,  therefore  believe  them  to  be 
true  appendages  of  the  eleventh  abdominal  segment.  It  is  obvious  that 
they  can  not  be  homologous  with  the  anal  larvapods  of  other  tenthredinoid 
larvae.  Crampton  (1919)  designated  them  as  arthrostyli  on  the  ground 
that  they  are  apparently  homologous  with  the  styli  of  the  Ephemeridae 
and  other  insects.  The  opinions  of  entomologists  differ,  for  example 
Middle  ton  (1921)  homologizes  the  subanal  appendages  with  the  post- 
pedes  of  Crampton.  The  homology  and  function  of  these  appendages 
need  further  investigation.  However,  it  is  significant  that  long  distinctly 
segmented  appendages  should  occur  in  the  Pamphiliidae  and  rudimentary 
ones  in  the  Cephidae. 

Larvapods. — The  embryological  data  seem  on  the  whole  to  support 
the  view  expressed  by  Korschelt  and  Heider  (1899),  who  say  that  "the 
abdominal  appendages  of  the  caterpillars  of  the  Lepidoptera  and  Hymen- 
optera  are  to  be  regarded  as  true  limbs,"  and  that  "limb-rudiments  first 
form  on  all  or  most  of  the  abdominal  segments,  but  they  very  soon  dis- 
appear on  those  segments  which  in  the  larvae  have  no  limbs,  while  on  the 
other  segments  they  are  transformed  into  the  functional  prolegs."  Graber 
(1890)  has  shown  that  the  so-called  anal  prolegs  of  Hylotoma  are  the 
appendages  belonging  to  the  tenth  or  true  penultimate  abdominal  segment. 
They  are,  therefore,  not  homologous  with  the  anal  "prolegs"  of  lepidop- 
terous larvae,  which  are,  according  to  Graber  (1890),  the  appendages  of 
the  ultimate  segment. 

The  maximum  number  of  larvapods  (pig)  occurs  in  the  Xyelidae,  where 
each  of  the  abdominal  segments  is  provided  with  a  pair.  The  first  and 
ninth  pairs  may  be  smaller  than  the  others,  as  in  Odontophyes,  but  they 
are  always  discernible.  The  number  of  larvapods  present  in  the  Tenthredin- 
idae  varies  from  six  to  eight  pairs.  They  are  usually  present  on  abdominal 
segments  2-7  and  10  or  2-8  and  10,  rarely  on  2-6  and  10.  In  the  Fenusinae 
(Fig.  105)  and  Caulocampus  the  tenth  pair  is  obsolete,  and  in  Metallus 
(Fig.  103)  they  are  fused  together  forming  a  median  protuberance. 
Larvapods  are  entirely  wanting  in  the  other  families  of  the  Tenthredinoidea. 


30  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [348 

A  typical  larvapod  is  a  fleshy  subconical  protuberance  narrowed  toward 
the  distal  end,  and  is  usually  subdivided  into  a  larger  but  shorter  proximal 
portion  and  a  smaller  but  longer  distal  portion.  Sometimes  the  distal 
end  is  dilated  and  turned  mesad,  as  in  Neodiprion  (Fig.  82),  or  the  cephalo- 
ventral  angle  is  pointed,  as  in  Tenthredo.  The  larvapods  are  well  devel- 
oped in  most  of  the  free-living  larvae  but  in  the  leaf-miners  and 
fruit-borers  they  are  reduced  and  smaller.  They  are  very  small  in  the  Hylo- 
tominae  and  rudimentary  in  the  Fenusinae  (Fig.  86)  and  Schizocerinae, 
while  they  are  obsolete  in  Phlebatrophia.  The  degree  of  development  of 
the  larvapods  is  closely  correlated  with  the  habits  of  the  larva.  The 
larvapods  are  usually  located  on  the  middle  of  each  lateral  half  of  the 
sternum  but  occasionally  are  very  close  together  near  the  meson,  as  in 
Neodiprion.  The  number  of  pairs  of  larvapods  present  is  a  convenient 
character  for  differentiating  the  subfamilies  of  the  Tenthredinidae.  The 
larvapods  often  bear  a  few  setae  on  the  cephalic  and  lateral  aspects. 
The  setae,  when  present,  are  confined  to  the  mesal  aspect.  Lack  of  setae 
on  the  larvapods  is  often  a  generic  character  and  the  number  and  arrange- 
ment of  the  setae  is  typical  of  the  species. 

Crampton  (1919),  with  good  reasons,  proposed  to  substitute  the  term 
uropods  for  the  long-used  but  misleading  term  prolegs.  The  term  uropoda 
has  been  employed  by  students  of  the  Crustacea  in  designating  the  abdom- 
inal appendages,  especially  one  of  the  posterior  pairs  of  pleopods,  and 
according  to  Smith's  glossary  of  Entomology  the  term  refers  to  "any  of 
the  abdominal  feet  of  Arthropoda."  These  facts  indicate  the  necessity  of  a 
distinctive  term,  and  the  new  term  larvapods  following  the  suggestion  of 
Dr.  MacGillivray,  is  used  until  a  happier  term  is  created  for  these  true 
abdominal  appendages  of  insect  larvae. 

Metamerism. — Graber  (1890)  has  shown  that  the  number  of  somites 
which  compose  the  body  of  the  larvae  of  Hylotoma  is  fourteen  exclusive 
of  the  head.  The  first  three  somites  belong  to  the  thorax  and  the  remaining 
eleven  to  the  abdomen.  The  ultimate  segment,  or  the  telson  of  the  embry- 
ologists,  is  difficult  to  discern  in  larvae.  It  is  probably  represented  by  the 
suranal  and  subanal  lobes  of  the  larvae,  but  the  boundary  between  this 
segment  and  the  tenth  somite  is  so  obliterated,  and  the  ultimate  segment, 
which  is  originally  much  smaller  than  the  preceding  somites,  is  in  the 
larval  stage  so  much  more  reduced,  that  it  is  permissible  and  also  con- 
venient to  speak  of  the  abdomen  as  being  composed  of  ten  segments. 
For  this  reason  the  tenth  abdominal  somite,  which  bears  the  so-called 
anal  prolegs,  is  designated  as  the  ultimate  segment  in  this  paper.  It  is  to  be 
noted  that  Nelson  (1915:111)  considers  that  there  are  eleven  segments 
and  a  telson  in  the  abdomen  of  the  embryos  of  Hymenoptera.  In  all  the 
larvae  of  the  Tenthredinoidea  examined,  it  is  always  possible  to  count 
ten  abdominal  segments.    The  body  is  usually  distinctly  segmented. 


349]  LARVAE  OF  THE  TENTHREDINOIDEA-^YUASA  31 

The  exact  limit  of  the  somite  in  a  larva  is  not  easy  to  determine. 
Entomologists  seem  to  have  paid  little  or  no  attention  to  this  point. 
Castle  (1900)  has  made  an  excellent  study  of  the  metamerism  of  the 
Hirudinea,  but  his  conclusions  are  not  directly  applicable  to  the  case  of  in- 
sect larvae  tho  they  are  pregnant  with  important  suggestions.  He  found 
that  the  natural  and  true  limits  of  a  somite  coincide  with  the  limits  of  the 
neuromere,  and  that  both  reduction  and  increase  in  the  number  of  rings, 
which  correspond  to  the  annulets  in  the  saw-fly  larvae,  take  place  at  the 
ends  of  the  segment.  The  classical  work  of  Lyonet  (1762)  and  the  recent 
study  of  Forbes  (1914)  on  the  musculature  of  lepidopterous  larvae,  as  also 
a  study  of  Boving  (1914)  indicate  that  the  musculature  affords  a  reliable 
criterion  for  determining  the  limits  of  a  somite.  From  a  careful  examina- 
tion of  the  musculature  of  various  types  of  tenthredinoid  larvae  (Fig.  129), 
the  author  has  come  to  the  conclusion  that  in  these  larvae  the  natural 
and  accurate  determination  of  the  extent  of  the  somites  composing  the 
body  is  best  based  upon  the  musculature.  A  detailed  discussion  of  this 
subject  is  out  of  place  here.  It  is  sufficient  to  say  that  a  majority  of  the 
longitudinal  muscles,  including  the  dorsal,  lateral,  and  ventral  retractor 
muscles,  originate  on  the  cuticular  fold,  or  coria,  which,  on  the  exterior,  is 
usually  indicated  by  a  deep  depression  (is).  Only  a  few  muscles  of  impor- 
tance cross  this  fold,  nearly  all  the  muscles  being  attached  either  to  the 
cephalic  or  caudal  part  of  the  coria.  This  cuticular  fold,  therefore,  is  con- 
sidered as  the  cephalic  limit  of  the  somite,  and  the  annulets  into  which 
the  somite  is  subdivided  are  numbered  consecutively,  commencing  at  its 
cephalic  end.  To  assume,  a  priori,  the  spiracular  annulet,  or  the  annulet 
which  bears  the  spiracle,  to  be  the  first  annulet  is  arbitrary  and  inaccurate 
inasmuch  as  this  annulet,  according  to  the  criterion  of  musculature,  cor- 
responds to  any  one  of  the  first  three  annulets  of  the  somite.  The  position 
of  the  spiracular  annulet  is  constant  and  definite  within  a  genus  or  sub- 
family as  long  as  the  number  of  annulets  of  the  somite  is  constant.  Some 
of  the  annulets  are  usually  setiferous  and  often  bear  in  addition  transverse 
rows  of  glandubae.  The  position  of  such  setiferous  annulets  is  constant  within 
the  genus  or  subfamily  when  the  annulation  is  constant.  The  number  of 
annulets  on  the  ninth  abdominal  segment  is  always  smaller  than  that  on 
the  preceding  segments.  Since  the  setiferous  annulets  have  a  definite 
order,  it  is  possible  to  determine  which  annulets  are  obsolete  on  the  penul- 
timate segment.  The  first  annulet  to  disappear  is  a  caudal  one,  and 
ordinarily  it  is  only  the  caudal  annulet  that  is  missing.  The  number  of 
annulets  of  the  sternum  is  less  than  that  of  the  tergum.  The  length  of 
the  annulets  varies  but  their  relative  size  is  constant  within  a  species. 
The  primitive  number  of  annulets  of  the  abdominal  segments  is  unknown. 
If  the  annulation  of  the  generalized  Tenthredinoidea  is  assumed  to  be 
representative  of  the  primitive  condition,  then  four  is  the  primitive  num- 


32  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [350 

ber  of  annulets.  In  the  specialized  Tenthredinoidea  the  number  varies 
from  one  to  seven,  but  five  to  seven  is  of  the  most  common  occurrence. 
The  number  becomes  smaller  in  the  highly  specialized  families,  being 
reduced  to  a  single  annulet  in  the  Siricidae  and  Orysidae. 

Spiracles. — The  spiracles  (spi)  are  present  on  the  prothorax  and  the 
first  eight  abdominal  segments  in  all  Tenthredinoidea.  The  pair  on  the 
prothorax  are  always  the  largest.  The  abdominal  spiracles  are  usually 
uniform  in  size  and  shape  except  the  last  pair,  which  are  often  larger  than 
the  others.  The  spiracles  are  definite  in  location  in  regard  to  the  annulets 
and  are  always  situated  on  some  one  of  the  first  three  annulets  of  the 
segments.  The  spiracular  line  is  usually  located  slightly  ventrad  of  the 
middle  of  the  lateral  aspect  of  the  body,  but  sometimes  it  migrates  ven- 
trad to  the  latero- ventral  line  as  in  Caliroa.  The  spiracles  (Fig.  155)  are 
usually  very  simple  in  structure,  vertical  in  position,  never  circular  in 
outline  but  narrowly  ovate,  rounded  or  pointed  at  both  ends.  The  peri- 
treme  is  narrow  but  strongly  chitinized  and  brownish  or  blackish.  The 
labiae  are  narrow  and  the  spiracular  opening  is  usually  closed  and  appears 
like  a  dark  line.  The  peritreme  is  sometimes  distinctly  thickened  as  in  the 
Hylotominae.  There  is  often  a  semicircular  or  irregular  chitinized  colored 
area  on  each  side  of  the  spiracles,  as  in  certain  nematid  genera.  These 
areas  vary  in  size  and  shape  but  are  constant  within  species,  and  their 
presence  is  usually  constant  within  genera  and  often  within  a  subfamily. 
When  these  areas  are  present,  the  spiracles  are  said  to  be  winged. 

The  true  prothoracic  spiracles  are  considered  as  wanting  in  adult  and 
larval  insects.  The  spiracles  found  on  the  prothorax  of  Tenthredinoid 
larvae  are  the  mesothoracic  spiracles  (msp)  which  have  migrated  from 
the  mesocoria  onto  the  prothorax.  The  metathoracic  pair  (tsp)  is  usually 
functionless,  very  small,  and  located  in  the  metacoria,  or  obsolete.  In  the 
Cephidae  and  Siricidae,  however,  the  metaspiracles  are  distinct,  functional, 
and  as  large  as  the  abdominal  spiracles.  It  is  difficult  to  explain  the 
rudimentary  condition  of  this  pair  in  the  Xiphydriidae,  since  other  charac- 
ters indicate  that  they  have  a  common  origin  with  the  Cephidae  and 
Siricidae.  It  is  possible,  however,  in  the  course  of  evolution,  to  have  one 
structure  of  the  body  modified  faster  than  another  structure. 

Setae. — The  surface  of  the  body  is  usually  provided  with  some  setae, 
particularly  on  the  head,  thoracic  legs,  and  the  ultimate  segment  of  the 
abdomen  on  the  suranal  and  subanal  lobes.  The  number,  size,  arrange- 
ment, and  structure  of  the  setae  vary  in  different  taxonomic  units,  accord- 
ing to  their  location;  and  to  some  extent  according  to  the  stage  of  larval 
growth.  There  is  a  tendency  toward  the  loss  of  setae  in  the  ultimate 
stage  or  the  last  instar,  as  is  Pteronidea,  or  to  have  fewer  and  smaller  setae 
in  the  leaf-mining  and  wood-boring  larvae,  as  in  the  Fenusinae,  Cephidae, 
and  others.    There  seem  to  be  no  definite  setal  patters,  as  in  lepidopterous 


351]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  33 

larvae,  but  when  certain  annulets  of  the  segments  possess  setae  their  pres- 
ence on  these  annulets  in  successive  segments  is  constant  if  not  in  precisely 
the  same  number  and  order.  There  is  a  tendency  to  have  more  and  longer 
setae  on  the  lower  half  of  the  head  than. on  the  upper  half.  The  number 
and  arrangement  of  the  setae  are  variable  on  the  vertex  and  front  but  are 
fairly  constant  on  the  clypeus,  labrum,  and  mandibles. 

A  spinal  formula  is  an  abbreviated  expression  of  the  arrangement  of 
the  tubercles  or  spines  on  the  various  parts  of  the  body.  The  figures  of 
the  formula  indicate  the  number  of  branches  of  a  spine  and  are  arranged  in 
order,  beginning  with  the  mesal  spine  in  the  case  of  those  on  an  annulet 
and  with  the  cephalic  spine  in  the  case  of  the  subspiracular  areas.  The 
spinal  formula  of  the  prothoracic  segment  represents  the  arrangement  of 
the  spines  on  the  large  or  second  annulet,  on  the  first  or  smaller  lateral 
annulet,  on  the  subspiracular  area,  and  on  the  postsubspiracular  area 
respectively.  The  spinal  formula  of  the  third  abdominal  segment  indicates 
the  arrangement  of  the  spines  on  the  first  tubercle-bearing  (usually  2d) 
annulet,  on  the  next  small  annulet  if  this  is  present,  on  the  third  tubercle- 
bearing  (usually  4th)  annulet,  on  the  subspiracular  area,  and  on  the  post- 
subspiracular or  surpedal  area,  respectively. 

The  number  of  branches  of  the  spines  sometimes  varies  and  the  arrange- 
ment of  the  spines  also  may  show  minor  variations.  The  spinal  formulae 
represent  the  most  typical  arrangement. 

Glands  and  Glandubae. — There  are  many  types  of  glands  opening  to  the 
exterior  found  on  the  various  parts  of  the  body  of  the  larvae  of  the  Tenth- 
redinoidea.  The  larvae  of  the  Nematinae  and  Cladiinae  are  provided  with 
a  series  of  ventral  glands  on  the  ventro-meson  of  abdominal  segments 
1-7.  Sometimes  a  pair  of  eversible  glands  is  found  in  the  cervical  region, 
as  in  Megaxyela  major.  The  larvae  of  the  Cimbicinae  possess  a  spiracular 
gland  located  dorsad  of  each  spiracle  of  abdominal  segments  2-8.  It  is  from 
these  glands  that  the  yellowish  fluid  of  these  larvae  is  poured  out  when 
disturbed.  A  peculiar  sucker-like  protuberance  with  a  depressed  center 
occurs  in  the  larvae  of  the  Acordulecerinae  on  the  sublateral  area  of 
abdominal  segments  2-4  or  5  and  8.  The  function  of  this  structure  is  not 
known  but  it  is  not  improbable  that  it  is  secretory  in  nature.  The  wax 
glands  of  the  wax-secreting  larvae  such  as  certain  Tenthredininae,  Emphy- 
tinae,  Selandriinae,  etc.,  are  minute  and  located  on  various  parts  of  the 
body  of  these  larvae,  but  their  detailed  structure  has  not  been  studied. 
The  most  common  type  of  these  glands  is  found  in  the  larvae  of  the 
Diprioninae,  Emphytinae,  Selandriinae,  Tenthredininae,  some  Nematinae, 
and  others.  The  cutaneous  glands  of  these  larvae  are  provided  with  chi- 
tinized  rings  about  their  external  openings.  These  chitinized  openings  are 
known  as  glandubae.  They  may  be  located  at  the  end  of  tubular  protu- 
berances, and  in  such  cases  they  are  spoken  of  as  being  stalked,  or  they 


34  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [352 

may  be  found  flush  with  the  body  surface,  when  they  are  spoken  of  as  being 
sessile.  The  glandubae  are  especially  conspicuous  in  the  larvae  of  the 
Diprioninae  and  Pachynematus.  The  slime-glands  of  Caliroa  have  semi- 
sessile  glandubae  which  are  few  in  number.  The  glandubae  are  constant 
in  their  type,  presence,  general  arrangement,  and  location,  within  genera 
and  subfamilies. 

Formulae  of  Segmented  Appendages. — For  convenience  in  designating 
the  size  and  relationship  of  various  segmented  appendages,  the  resort 
has  been  made  to  various  so-called  formulae.  The  segments  of  an  appen- 
dage are  numbered,  beginning  with  the  proximal  segment.  In  a  formula 
numbers  of  the  segments  are  arranged  in  the  descending  order  of  magni- 
tude, and  those  of  equal  dimensions  are  placed  in  a  parenthesis.  For 
example,  the  expression  "antennal  formula:  (2,5),  3,  4,  1"  shows  that  the 
antenna  is  composed  of  five  segments  and  that  segments  2  and  5  are  equal 
in  length  but  longer  than  the  others,  and  that  segment  4  is  shorter  than 
segment  3  but  longer  than  the  first  or  proximal  segment. 


353]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  35 


III.     TAXONOMY 

Strictly  speaking  no  classification  of  the  Tenthredinoidea  based  upon 
larval  characters  has  hitherto  been  proposed.  Attempts  have  been 
restricted  to  the  characterization  of  the  different  subdivisions  included  in 
the  superfamily.  Among  the  earlier  writers  Le  Pele tier's  (1823)  work  may 
be  mentioned.  After  a  brief  general  account  of  the  larvae,  he  gave  a  list 
of  eighteen  divisions  in  which  he  grouped  the  species  of  the  Tenthredinoidea 
and  stated  whether  the  larvae  of  each  division  were  known  or  unknown 
and,  if  known,  the  number  of  the  thoracic  and  abdominal  legs  present. 
It  is  interesting  to  note  that  he  mentioned  a  group  of  larvae  the  body  of 
which  he  characterized  as  "donkey-form"  (aselliform)  which  he  was 
unable  to  place  in  any  of  his  divisions.  Dahlbom  (1835)  published  careful 
descriptions  and  a  synopsis  of  larvae  of  sixty-three  species.  A  synoptic 
table  for  the  larvae  was  compiled  by  Westwood  (1840)  from  this  work 
and  was  published  with  additions.  The  characters  used  are  the  number  of 
abdominal  legs  and  the  feeding  habits  of  the  larvae.  Norton  (1867) 
republished  Westwood's  table  without  additions.  In  the  table  given  by 
Cameron  (1882)  the  larvae  of  more  than  ninety-five  species  are  included. 
The  major  groups  are  separated  on  the  number  of  thoracic  and  abdominal 
legs  present.  These  subdivisions  are  segregated  on  biological  characters 
such  as  reflex  bleeding,  types  of  cocoons,  and,  finally,  genera  and  species, 
when  known,  are  separated  on  the  coloration,  setae,  food-plants,  and  feed- 
ing habits.  In  1895  Dyar,  the  most  prolific  and  the  only  important  Ameri- 
can writer  on  the  larvae  of  the  Tenthredinoidea,  published  "A  recognition 
table  for  the  known  sawfly  larvae  of  the  North  Atlantic  States."  The 
larvae  of  one  hundred  and  twenty-six  species  including  forty-one  not 
specifically  identified  were  considered  in  this  synopsis.  The  characters 
used  are  the  number  and  location  of  abdominal  legs,  types  of  cocoon, 
feeding  habits,  food-plants,  and  coloration.  This  last  character  was 
employed  extensively  in  separating  different  species.  The  next  attempt 
along  this  line  was  undertaken  by  Chester  Young  (1898),  who  was  the 
first  to  take  into  consideration  the  structural  characters  of  the  appendages 
of  the  head.  Unfortunately  this  work  remains  unpublished,  but  it  is  on 
file  as  a  baccalaureate  thesis  in  the  library  of  Cornell  University.  Konow 
(1901)  summarized  the  taxonomic  information  concerning  the  known 
larvae  of  European  and  American  species,  four  hundred  and  eighteen  in 
all,  in  the  form  of  an  analytical  table.  The  presence  or  absence  of  abdom- 
inal legs,  number  of  antennal  segments,  and  modifications  and  appendages 


36  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [354 

of  the  ultimate  body-segment  were  used  in  separating  the  families  and 
subfamilies.  The  number  and  location  of  abdominal  legs,  the  food-plants, 
types  of  cocoon,  and  coloration  furnished  the  basis  for  the  separation  of 
tribes,  genera,  and  species.  Middleton  (1915,  1917)  has  characterized  the 
larvae  of  the  genus  Dimorphopteryx  and  of  the  family  Cephidae.  It 
must  be  noted  that  these  writers  were  concerned  only  in  the  preparation 
of  recognition  tables  for  the  separation  of  the  particular  species  they  had 
in  hand,  and,  with  the  exception  of  Middleton,  no  one  has  attempted 
to  construct  a  synopsis  of  families,  genera,  and  species  as  such. 

In  the  following  pages,  the  author  has  attempted  to  define  and  describe, 
as  far  as  possible  with  the  materials  at  hand,  families,  subfamilies,  genera, 
and  species  by  the  use  of  larval  characters.  With  a  few  exceptions,  no 
attempt  has  been  made  to  incorporate  data  from  previous  writers  for  the 
reason  that  the  characters  recorded  by  them  were  found  in  most  cases  of 
little  or  no  value  for  the  present  purpose — not  because  they  were  inaccu- 
rate, altho  that  was  true  in  many  cases,  but  chiefly  because  they  were  not 
of  specific  significance.  For  example,  Dyar's  descriptions  of  species  are 
usually  very  accurate  and  dependable  but  most  of  the  characters  noted 
excepting  coloration  often  proved  to  be  only  of  family  or  subfamily  sig- 
nificance. The  definitions  given  here  are  correct  for  the  materials  actually 
studied,  but  it  is  not  surprising  if  they  do  not  hold  good  in  many  cases 
when  more  materials  become  available  for  examination.  It  is  obviously 
impossible  to  attain  perfection  in  the  face  of  so  many  missing  links  in  the 
series  of  genera  and  species.  These  missing  links  will  be  filled  in  as  rapidly 
as  accurately  identified  materials  become  available,  but  it  must  be  remem- 
bered that  absolutely  correct  identification  is  only  possible,  in  the  majority 
of  cases,  after  carrying  individual  larvae  of  the  species  thru  to  the  adult 
stage,  exuviae  being  saved  for  each  instar. 

In  this  study  the  classification  of  the  Tenthredinoidea  proposed  by 
MacGillivray  in  1906,  with  later  additions,  has  been  adopted  in  the  main 
in  arranging  and  restricting  the  families,  subfamilies,  genera,  and  species. 
For  generic  synonymy,  Rohwer's  "Genotype  of  the  Sawflies  and  Wood- 
wasps"  (1911)  has  been  followed.  In  this  section  all  references  to  the 
bibliography  of  the  different  divisions  and  subdivisions  have  been  omitted. 


355]  IARVAE  OF  THE  TENTHREDINOIDEA—YUASA  37 


SUPERFAMILY  TENTHREDINOIDEA 

Larvae  with  exposed,  well  differentiated  head,  trunk  consisting  of  three 
thoracic  and  ten  visible  abdominal  segments;  spiracles  always  present  on 
prothorax  and  first  eight  abdominal  segments;  antennae  and  chitinized 
dentate  mandibles  always  present;  ocellarae,  when  present,  always  one  on 
each  side  of  the  head;  thoracic  legs,  when  present,  always  three  pairs, 
a  pair  to  each  segment;  larvapods,  when  present,  always  six  pairs  or 
more,  and  except  the  Xyelidae,  are  never  on  the  first  and  ninth  abdominal 
segments,  but  always  on  the  second  abdominal  segment,  and  never  with 
crochets;  mouth-parts,  when  normal,  with  mandibles  strongly  chitinized 
with  distinct  dentes,  dextral  dentes  differing  in  number,  shape,  and 
arrangement  from  sinistral;  maxillae  with  cardo,  stipes,  palpifer,  palpus, 
galea,  and  lacinia  present,  palpus  typically  with  four  segments,  galea 
conical,  digit-like,  and  lacinia  usually  flattened,  its  cephalic  margin  with  a 
fringe  of  setae;  labium  with  submentum,  mentum,  palpi,  stipulae,  and 
totaglossa,  palpi  typically  with  three  segments,  totaglossa  membranous, 
bulbose,  with  a  sericos  on  its  meso-distal  portion;  general  appearance  of 
body  caterpillar-like  or  grub-like;  free  leaf -feeders,  leaf-miners,  web- 
spinners,  leaf-rollers,  wood-  and  stem-borers,  and  parasitic  larvae. 

Free  Leaf -feeders. — Body  caterpillar-like;  thorax  with  well-developed, 
distinctly  segmented  legs,  typically  with  five  segments,  coxa,  trochanter, 
femur,  tibia,  and  tarsus  and  tarsal  claw;  abdomen  typically  with  a  pair  of 
larvapods  on  segments  2-7  or  2-8  and  10;  ultimate  segment  sometimes 
with  caudal  protuberances  but  never  with  a  distinct  suranal  process  or  with 
subanal  appendages;  head  typically  semiglobose;  antennae  typically  mul- 
tisegmented,  segments  one  to  five  in  number;  ocellarae  always  present, 
usually  located  dorsad  of  antennariae;  mouth-parts  well  developed  and 
typical  in  structure;  abdominal  segments  usually  with  five  to  seven  annu- 
lets, some  of  which  bear  transverse  rows  of  setae  and  often  some  glandubae; 
head,  thoracic  legs,  and  anal  area  usually  setiferous;  majority  of  Tenthre- 
dinidae  and  Xyelidae. 

Leaf -miners. — Body  somewhat  depressed,  head  sometimes  distinctly 
depressed  and  mouth-parts  directed  cephalo-ventrad;  thoracic  legs  small, 
modified,  number  of  segments  reduced  to  four  or  to  one,  legs  sometimes 
entirely  fleshy,  conical,  or  mamma-like,  with  or  without  tarsal  claws; 
abdomen  with  very  small  larvapods  or  larvapods  nearly  obsolete;  mouth- 
parts  sometimes  modified,  labial  and  maxillary  palpi  with  reduced  number 


38  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (356 

of   segments;    annulation    sometimes   obsolete.      A   few   subfamilies   of 
Tenthredinidae. 

Nest-builders. — Thorax  with  seta-like  segmented  legs;  abdomen  without 
larvapods;  antennae  long,  setaceous,  seven-segmented;  mouth-parts  nor- 
mal; ultimate  segment  with  distinct  subanal  appendages  and  a  minute 
hook-like  caudal  process  on  caudo-meson  of  tergum;  ocellarae  present; 
web-spining  leaf-rollers,  Pamphiliidae.  - 

Borers. — Thorax  with  rudimentary  legs,  tarsal  claws  never  present; 
abdomen  without  larvapods,  ultimate  segment  with  a  distinct  suranal 
process  or  with  a  pair  of  subanal  appendages;  mouth-parts  somewhat 
modified,  maxillary  and  labial  palpi  reduced  in  number  of  segments; 
ocellarae  wanting  or  with  vestigial  eye-spots;  metaspiracles  sometimes 
functional,  as  large  as  abdominal  ones;  wood-borers  and  stem-borers. 
Siricidae,  Xiphydriidae,  and  Cephidae. 

Parasites. — Body  grub-like,  thoracic  and  abdominal  legs  wanting; 
mouth-parts  modified,  maxillary  and  labial  palpi  obsolete;  ocellarae 
wanting;  antennae  one-segmented;  parasitic  larvae,  Oryssidae. 

The  larvae  of  the  typical  Tenthredinoidea  are  readily  differentiated 
from  the  larvae  of  other  Entometabola  by  the  presence  of  a  single  ocellara 
on  each  side  of  the  head  and,  usually,  six  or  more  pairs  of  larvapods,  none 
of  which  are  provided  with  crotchets,  and  never  occur  on  first  and  ninth 
abdominal  segments.  The  characteristic  mouth-parts  include  four- 
segmented  maxillary  palpi  and  three-segmented  labial  palpi.  The  character 
of  the  antennae,  the  number  of  ocellarae  and  larvapods,  the  charac- 
ter of  the  mouth-parts,  especially  maxillary  and  labial  palpi,  and  the 
presence  of  thoracic  legs  distinguish  the  leaf-miners  and  wood-borers  of 
the  Tenthredinoidea  from  other  leaf-miners  and  wood-borers,  such  as 
certain  Lepidoptera,  Coleoptera,  and  Diptera.  The  larvae  of  Hymenop- 
tera  other  than  Tenthredinoidea  are  distinguishable  from  those  of  the 
latter  as  follows:  They  are  apodous,  thoracic  and  abdominal  legs  being 
always  wanting;  the  mouth-parts  are  vestigial,  maxillary  and  labial 
palpi,  if  present,  papilliform,  never  distinctly  segmented;  ocellarae  are 
never  present;  and  suranal  process  and  subanal  appendages  are  always 
wanting.  The  larvae  of  the  Oryssidae  are  separable  from  other  hymen- 
opterous  larvae  on  the  basis  of  the  characters  used  in  the  definition  of  that 
family  elsewhere. 

FAMILIES  OF  TENTHREDINOIDEA 

1(6)  Thoracic  legs  present,  either  normal  in  form,  distinctly  segmented,  or  modified,  if 
modified,  fleshy  or  conical,  if  conical,  head  and  body  distinctly  depressed;  larvapods 
either  present  or  wanting 2. 

2(5)  Thoracic  legs  normal  in  form,  not  seta-like,  rarely  mamma-like;  larvapods  usually 
present;  subanal  appendages  wanting;  antennae  usually  with  less  than  seven  seg- 
ments  3. 


357]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  39 

3(4)      Larvapods  present  on  all  abdominal  segments;  antennae  with  six  or  seven  segments. 

XYELIDAE. 
4(3)      Larvapods  not  present  on  all  abdominal  segments;  antennae  never  with  more  than  five 

segments TENTHREDINIDAE. 

5(2)      Thoracic  legs  seta-like;  larvapods  wanting;  subanal  appendages  present,  setaceous; 

antennae  very  long,  with  seven  segments PAMPHILIIDAE. 

6(1)      Thoracic  legs  vestigial,  not  distinctly  segmented,  mamma-like  or  wanting,  if  mamma- 
like, head  and  body  never  distinctly  depressed;  larvapods  wanting 7. 

7(12)    Thoracic  legs  present;  ultimate  segment  with  suranal  process 8. 

8(9)      Subanal  appendages  present,  vestigial,  papilliform;  ocellarae  present;  antennae 

with  four  or  five  segments CEPHIDAE. 

9(8)      Subanal  appendages  wanting;  ocellarae  wanting 10. 

10(11)    Antennae  with  three  segments;  metaspiracles  functionless,  very  much  smaller  than 

abdominal  spiracles 11. 

XIPHYDRIIDAE. 
11(10)    Antennae  with  one  segment;  metaspiracles  functional,  as  large  as  abdominal  spir- 
acles  SIRICIDAE. 

12(7)      Thoracic  legs  wanting;  ultimate  segment  without  suranal  process  and  subanal 
appendages ORYSSIDAE. 

MacGillivray  (1906)  divided  the  superfamily  Tenthredinoidea  into 
nine  families.  They  are  the  Xyelidae,  Pamphiliidae,  Blasticotomidae, 
Tenthredinidae,  Xiphydriidae,  Siricidae,  Megalodontidae,  Cephidae,  and 
Oryssidae.  The  first  two  families  constitute  his  Generalized  Tenthredinoi- 
dea and  the  last  six  his  Specialized  Tenthredinoidea.  Since  the  Blastico- 
tomidae and  Megalodontidae  belong  to  the  Palearctic  fauna  and  are  not 
represented  in  North  America,  they  are  omitted  from  the  foregoing  table. 

Family  Xyelidae 

Larvae  (Fig.  6)  of  medium  size,  length  13-18  mm.;  body  caterpillar 
like,  subcylindrical,  flattened  on  the  ventral  aspect,  uniform  in  diameter' 
except  last  two  segments  which  are  suddenly  constricted,  stout;  segmenta- 
tion and  usually  annulation  distinct;  cuticle  smooth,  tuberculate  and 
setiferous,  but  never  slimy;  color  greenish,  yellowish,  whitish,  or  brownish; 
tubercles,  when  present,  brownish  or  blackish  and  setiferous;  prothorax 
sometimes  with  a  pair  of  lateral  eversible  cervical  glands  in  the  cervacoria; 
head  circular  in  frontal  contour,  moderately  large,  width  usually  more 
than  one-half  the  diameter  of  the  thorax;  mouth  directed  ventrad;  head 
slightly  overlapped  by  the  prothorax,  if  any  setae,  sparsely  and  inconspi- 
cuously setiferous;  antennae  long,  conspicuous,  with  six,  sometimes 
seven,  segments;  ocularia  about  one-fifth  the  diameter  of  the  antennaria 
and  located  caudo-dorsad  of  it,  elevated,  ocellarae  very  small;  epicranial 
suture  and  vertical  furrows  present;  mouth-parts  normal  in  form;  pro- 
thorax with  a  large,  often  colored,  shield-like  area  on  the  dorsum  and 
lateral  aspects;  legs  in  comparison  with  the  size  of  the  body  very  small, 
normal  in  form,  all  three  pairs  subequal  in  size;  larvapods  present  on  all 


40  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [358 

abdominal  segments  including  the  first  and  ninth,  where  they  are  some- 
times reduced  in  size;  typical  segments  with  four  annulets;  spiracles  on  the 
second  annulet;  sublateral  lobe  produced  ventrad,  modified  into  a  triangu- 
lar lobe  laterad  of  larvapod  which  it  resembles  in  form;  ninth  abdominal 
tergum  with  three  annulets;  tenth  abdominal  tergum  constricted  distinctly 
and  transversely  on  its  cephalic  fourth  and  with  a  distinct  hump-like  protu- 
berance on  the  meson  caudad  of  the  cephalic  constriction,  concolorous  with 
the  head  and  setiferous  tuberlces;  anal  larvapods  and  ventral  or  subanal 
lobes  distinctly  large,  contiguous,  forming  a  trilobate  prominence  on  the 
meson  of  the  tenth  sternum;  subanal  lobe  with  a  pair  of  setiferous  protu- 
berances dorsad  of  larvapods;  insects  single-brooded,  solitary,  chiefly 
exposed-feeders;  pupate  in  earthen  cells  in  the  ground. 

The  Xyelidae  is  a  small  family  consisting  of  seven  genera  and  of 
a  limited  number  of  species,  most  of  which  belong  to  the  North  American 
fauna.  The  adults  are  readily  distinguished  from  all  other  Hymenop- 
tera  by  the  presence  of  the  free  part  of  the  vein  R2  in  the  wings.  On 
venational  characters,  MacGillivray  (1906)  considers  the  members  of  this 
family  to  be  the  most  generalized  Hymenoptera  known,  having,  "departed 
from  the  type  of  the  wing  assumed  for  the  original  progenitor  of  the 
Hymenoptera  only  in  the  loss  of  the  free  part  of  vein  Cu2."  The  genera, 
at  the  same  time,  possess  many  features  of  prominent  progressive  speciali- 
zations which  have  proceeded  in  each  case  in  a  different  sequence  so  that 
a  linear  arrangement  of  the  genera  does  not  express  their  true  affinities. 

Over  twenty-five  species  have  been  reported  from  boreal  America. 
Of  this  number,  four  species  belonging  to  as  many  genera  have  been  recog- 
nized in  the  larval  state.  Another  unidentified  species,  feeding  on  pecan, 
is  added  in  this  paper.  Dyar  (1898)  described  the  larvae  of  Megaxyela 
major  and  Xyela  minor  and  gave  a  definition  of  the  family  based  on  charac- 
ters found  in  these  species.  He  pointed  out  that  they  are  most  nearly 
related  to  the  Pamphiliidae.  The  larvae  of  Odontophyes  aviingrata  were 
described  by  the  same  author  (1899).  Konow  (1901)  overlooked  Dyar's 
1898  paper  and  gave  in  his  analytical  table  for  the  larvae  Odontophyes 
aviingrata  as  the  sole  representative  of  the  subfamily  Xyelini.  That 
Konow  was  unfamiliar  with  any  xyelid  larvae  may  be  reasonably  assumed 
from  the  fact  that  he  classified  them  with  those  larvae  which  had  no 
larvapods  and  that  he  placed  a  question  mark  before  the  analytical  item 
"ohne  Afterborsten."  The  larvae  of  Pleuroneura,  Paraxyela  and  Proto- 
xyela  are  unknown.  The  described  larvae  feed  on  the  foliage  of  hickory, 
butternut,  pecan,  elm,  and  the  staminate  flowers  of  pine. 

The  most  important  materials  that  I  had  in  the  study  of  this  family 
were  received  from  Professor  R.  W.  Harned,  of  the  Mississippi  Agricultural 
College,  but,  altogether,  the  material  at  hand  is  so  limited  that  it  does 


359]  LARVAE  OF  THE  TENTHRED1N01DEA—YUASA  41 

not  permit  a  characterization  of  the  genera.  The  following  key  will  serve  to 
separate  the  species: 

1  (8)  Larvapods  present  on  all  abdominal  segments,  those  on  the  first  and  ninth  segment 
sometimes  rudimentary;  thoracic  legs  normal  in  form;  body  tuberculate,  tubercles 
setiferous,  concolorous  with  the  head;  head  creamy  or  brownish  or  blackish;  abdom- 
inal segments  typically  with  four  annulets,  first  annulet  smooth,  non-tuberculate, 
crescentic,  and  confined  to  the  dorsal  aspect,  three  following  annulets  convex,  with 
transverse  row  of  setiferous  tubercles;  not  on  staminate  flowers  of  conifers 2. 

2(7)  Head  dark-colored,  brownish  or  blackish;  tenth  abdominal  tergum  always  and 
prothoracic  and  ninth  abdominal  terga  usually  with  dark-colored  patches;  tenth 
tergum  brownish  or  blackish;  subanal  lobe  with  a  pair  of  wart-like  brown  tubercles 
which  bear  blackish  brown  setae  on  the  dorsal  and  lateral  aspects,  less  densely  on 
the  ventral  aspect;  dorsal  tubercles  arranged  typically  as  follows:  the  second  and 
third  annulets  with  four  to  five,  the  fourth  annulet  with  two  or  three;  the  subspiracu- 
Iar  and  surpedal  lobes,  each  with  a  tubercle;  the  dorsal  tubercles  of  the  second  annu- 
let with  one  to  three  setae 3. 

3(6)  Tubercles  of  typical  abdominal  segment  arranged  as  follows:  second  and  third 
annulets  with  four  tubercles  above  the  spiracular  line,  each  tubercle  bearing  one 
seta,  the  fourth  annulet  with  two  tubercles,  one  on  the  spiracular  line  with  two  setae, 
the  other,  dorsad  of  the  line,  with  one  seta;  on  hickory  and  pecan 4. 

4(5)  Prothoracic  tergum  with  a  large  dark  brown,  median  patch  whose  lateral  margins 
converge  toward  the  cephalic  margin,  which  is  one-half  as  long  as  the  caudal  margin; 
the  ninth  abdominal  tergum  with  a  large  dark  brownish  patch  on  each  side  of  the 
meson,  the  patches  converging  toward  the  caudal  margin  so  that  the  caudal  halves 
are  nearly  confluent  on  the  meson  with  a  pair  of  brownish  tubercles  btween  the 
cephalic  halves;  tenth  abdominal  tergum  almost  completely  dark  brown  in  color; 
the  first  annulet  of  typical  segment  with  the  dorsal  pair  of  tubercles  quadrate,  one- 
half  as  long  as  the  annulet;  abdomen  with  a  brownish,  cloudy,  longitudinal  dorso- 
lateral line  involving  the  dorsal  pair  of  tubercles  and  extending  usually  from  the 

second  abdominal  segment  to  the  seventh;  on  hickory  and  pecan;  Y-226,  G 

Megaxayela  major  Cresson. 

5(4)  Prothoracic  tergum  without  a  large  dark  brownish  median  patch,  but  with  a  pair  of 
small  blackish  patches  distinctly  separated  on  the  meson  of  the  first  and  second 
annulets,  the  cephalic  pair  larger,  triangular,  and  their  apices  directed  laterad,  the 
caudal  pair  subquadrate,  further  apart  than  the  cephalic  pair;  the  ninth  abdominal 
tergum  without  a  pair  of  large  dark  brownish  patches  but  with  two  pairs  of  small 
blackish  patches,  distinctly  separated  on  the  meson,  the  cephalic  pair  smaller  and 
slightly  further  apart  than  the  caudal  pair;  tenth  tergum  blackish,  with  its  cephalic 
constricted  portion  pale  or  creamy;  first  annulet  of  typical  abdominal  segment  with 
the  dorsal  pair  of  tubercles  subcircular,  one-third  as  long  as  the  annulet;  abdomen 

without  a  brownish,  cloudy  longitudinal  dorso-mesal  lines;  on  pecan;  Y-227 

Megaxyela  sp.  1. 

6(3)  Tubercles  of  a  typical  abdominal  segment  arranged  as  follows:  second  and  third 
annulets  with  four  to  five  tubercles  above  the  spiracular  line,  each  tubercle  bearing 
two  setae;  the  fourth  annulet  with  three  tubercles,  one  on  the  spiracular  line  and  the 
other  two  dorsad  of  it,  each  tubercle  with  two  setae;  on  hickory  and  butternut; 
Y-228 ; Odontophyes  aviingrata  Dyar. 

7(2)  Head  light  in  color,  creamy  white  or  pale  brown;  the  prothoracic  and  the  ninth 
and  tenth  abdominal  terga  without  dark-colored  patches;  tenth  tergum  light  brown; 
subanal  lobe  with  a  pair  of  wart-like  creamy  tubercles  which  bear  long  light  brown 


42  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [360 

setae,  uniformly  distributed  on  all  aspects;  tubercles  arranged  as  follows:  the  second 
and  third  annulets  with  four  tubercles  dorsad  of  the  spiracular  line,  the  second 
tubercle  dorsad  of  the  ventral  one  sometimes  rudimentary  and  often  represented  by 
a  single  tiny  seta,  the  fourth  annulet  with  two  tubercles,  one  on  the  spiracular  line 
and  the  other  dorsad  of  it,  the  sublateral  area  divided  into  three  lobes  and  each 
with  one  tubercle;  the  dorsal  pair  of  tubercles  of  the  first  annulet  with  four  to  five 

setae;  on  Ulmus;  G Macroxyda  ferruginea  Say. 

8(1)  Larvapods  very  small;  thoracic  legs  rudimentary;  body  not  tuberculate;  head 
creamy  white ;  abdominai  segments  typically  with  three  annulets;  on  stamina te  flowers 
of  pine  (Dyar  in  1898  described  no  larvapods) Xyda  minor  Dyar. 

Family  Blasticotomidae 

The  Blasticotomidae  contains  a  single  genus  and  species,  Blasticotoma 
filiceti  Klug,  which  is  confined  to  central  and  eastern  Europe.  It  is  an 
archaic  type.  The  systematic  position  of  this  unique  species  has  been 
considered  differently  by  practically  every  writer  who  has  studied  it. 
MacGillivray  (1906)  has  shown,  however,  that  it  is  in  certain  of  its  charac- 
ters closely  allied  to  the  Xyelidae  and  Pamphiliidae,  while  in  others  it 
approximates  the  Tenthredinidae,  and  that,  it  is  intermediate  in  position 
between  these  two  groups. 

Because  of  its  taxonomic  position,  it  is  highly  desirable  to  know  the 
characters  of  the  larvae  of  this  species,  but  unfortunately  the  literature  is 
void  of  information  in  regard  to  the  immature  stages,  and  this  interesting 
quest  must  await  future  discoveries. 

Family  Tenthredinidae 

Larvae  (Figs.  7-25)  very  small  to  very  large,  length  10-40  mm.;  cater- 
pillar-like, leaf -feeders,  leaf-miners,  or  fruit-borers;  body  cylindrical, 
thorax  usually  largest  in  diameter,  body  tapering  caudad,  sometimes 
flattened  on  the  ventral  aspect,  leaf-miners  depressed;  greenish  or  variously 
colored  with  or  without  distinct  markings;  smooth,  glabrous,  setiferous, 
tuberculate,  or  spinous;  segmentation  usually  and  annulation  sometimes 
distinct;  third  abdominal  segment  with  6,  7,  5,  4,  3,  or  2  annulets,  men- 
tioned in  the  order  of  frequency;  some  of  annulets  usually  setiferous  and 
often  with  glandubae;  thoracic  legs  always  present,  usually  well  developed, 
typically  with  five  segments,  sometimes  with  three,  four,  or  six  segments, 
but  always  with  distinct  tarsal  claws;  legs  rarely  rudimentary,  fleshy, 
indistinctly  segmented,  and  without  tarsal  claws;  larvapods  present 
usually  on  abdominal  segments  2-7  and  10  or  2-8  and  10,  occasionally  the 
seventh  and  tenth  pairs  wanting,  rarely  with  all  larvapods  obsolete;  head 
typically  semiglobose,  setiferous,  with  or  without  distinct  markings  or  uni- 
formly brownish,  blackish,  or  greenish;  antennae  always  present,  never  with 
more  than  five  segments;  ocellarae  always  present,  one  on  each  side; 


361]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  43 

maxillary  and  labial  palpi  typically  with  four  and  three  segments  respec- 
tively, never  obsolete,  number  of  segments  rarely  reduced;  clypeus  usually 
with  two  or  three  setae  on  each  side;  mandibles  usually  with  one  to  four 
setae;  tenth  abdominal  tergum  without  suranal  process  and  sometimes 
with  caudal  protuberances;  subanal  appendages  never  present;  epicranial 
suture  and  vertical  furrows  usually  present;  metaspiracles  functionless, 
obsolete,  or  very  much  smaller  than  abdominal  spiracles;  various  glands 
sometimes  present. 

The  family  Tenthredinidae  according  to  MacGillivray  contains  twenty- 
four  subfamilies  of  which  five  are  not  represented  in  the  Nearctic 
fauna.  The  subfamilies  found  in  the  United  States  and  Canada  are  as 
follows:  Diprioninae,  Emphytinae,  Selandriinae,  Dolerinae,  Phyllotominae, 
Lycaotinae,  Tenthredininae,  Cimbicinae,  Hoplocampinae,  Dineurinae, 
Monocteninae,  Cladiinae,  Nematinae,  Blennocampinae,  Fenusinae,  Sco- 
lioneurinae,  Hylotominae,  Schizocerinae,  and  Acordulecerinae.  Of  these, 
Lycaotinae  and  Dineurinae  have  not  been  available  for  study. 

SUBFAMILIES  OF  TENTHREDINIDAE 

1(42)    Thoracic  legs  normal  in  form,  five-segmented;  if  modified,  tarsal  claws  always 

present;  larvapods  usually  well  developed 2. 

2(23)    Larvapods  present  on  abdominal  segments  2-8  and  10;  antennae  elongate,  conical, 

usually  with  five  segments 3. 

3(20)    Thoracic  legs  with  five  segments,  normal  in  form 4. 

4(11)    Third  abdominal  segment  with  six  annulets  on  dorsum 5. 

5(10)    Antennae  conical,  with  five  segments 6. 

6(9)      Labrum  bilaterally  symmetrical;  legs  with  tibia  shorter  than  femur,  tarsal  claws 

short,  strongly  curved 7. 

7(8)  Body  rather  slender,  tapering  caudad,  without  small  distinct  tubercles;  tenth 
abdominal  tergum  without  small  tubercles;  head  never  shiny,  jet-black,  body  never 

yellowish  white EMPHYTINAE  (in  part). 

8(7)  Body  rather  robust,  uniform  in  diameter  thruout,  with  small  distinct  tubercles;  tenth 
abdominal  tergum  with  several  small  protuberances,  if  without,  head  shiny,  jet- 
black,  body  yellowish  white BLENNOCAMPINAE  (in  part). 

9(6)      Labrum  not  bilaterally  symmetrical,  but  distinctly  asymmetrical;  legs  with  tibia 

longer  than  femur,  tarsal  claws  slender,  only  slightly  curved DOLERINAE. 

10(5)      Antennae  not  conical,  with  three  segments,  the  third  segment  erect  and  peg-like. 

DIPRIONINAE. 

11(4)      Third  abdominal  segment  with  more  or  less  than  six  annulets  on  dorsum 12. 

12(19)    Third  abdominal  segment  with  seven  annulets  on  dorsum;  body  without  conspicuous 

branched  spines  or  tubercles 13. 

13(18)     Antennae  conical,  with  five  segments;  labrum  without  secondary  longitudinal 

sutures 14. 

14(15)    Larvapods  setiferous;  clypeus  with  three  setae  on  each  side;  mandible  with  two 
setae;  labrum  without  a  median  longitudinal  depression . .  SELANDRIINAE  (in  part) . 

EMPHYTINAE  (in  part). 

15(14)     Larvapods  glabrous;  clypeus  with  two  setae  on  each  side;  mandible  with  1-4  setae; 

labrum  with  or  without  a  median  longitudinal  depression 16. 


44  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (362 

16(17)  Legs  with  tibia  minute,  distinctly  shorter  and  smaller  than  femur;  maxillae  with 
stipes  without  cephalo-ventral  triangular  projection;  mandibles  with  two  setae; 

labrum  without  a  median  longitudinal  depression 17. 

SELANDRIINAE  (in  part). 

17(16)  Legs  with  tibia  large,  usually  subequal  to  or  longer  than  femur;  maxillae  with  stipes 
with  cephalo-ventral  triangular  projection;  mandibles  with  1,  2,  or  3-4  setae;  labrum 
with  or  without  a  median  longitudinal  depression TENTHREDININAE. 

18(13)  Antennae  not  conical,  with  one  segment;  labrum  with  secondary  longitudinal 
sutures;  small  but  distinct  crescentic  glandubae  dorsad  of  spiracles.  CIMBICINAE. 

19(12)  Third  abdominal  segment  with  five,  rarely  three  or  four,  annulets  on  dorsum; 
body  with  conspicuous  branched  spines  or  tubercles.  BLENNOCAMPINAE  (in  part) . 

20(3)      Thoracic  legs  with  four  segments,  modified 21. 

21(22)  Tenth  urotergum  and  prothoracic  and  mesothoracic  tergites  with  conspicuous  fleshy 
pointed  protuberances;  body  not  tadpole-like EMPHYTINAE  (in  part). 

22(21)  Tenth  urotergum  and  prothoracic  and  mesothoracic  tergites  without  conspicuous 
fleshy  pointed  protuberances;  body  often  distinctly  tadpole-like. 

PHYLLOTOMINAE  (in  part). 

23(2)  Larvapods  on  abdominal  segments  2-7  and  10,  rarely  on  segments  2-7  or  2-6  and 
10 24. 

24(39)  Thoracic  legs  with  five  segments,  normal  in  form;  larvapods  on  segments  2-7  and 
either  with  or  without  anal  larvapods 25. 

25(36)  Larvapods  present  on  the  ultimate  segment,  either  normal  and  separated  or  fused 
on  the  meson,  forming  a  single  prominence 26. 

26(35)     Anal  larvapods  normal  and  separated 27. 

27(28)  Antennae  with  five  segments;  third  abdominal  segment  with  six  annulets;  tenth 
abdominal  tergum  with  several  caudal  protuberances.  HOPLOCAMPINAE  (in  part). 

28(27)  Antennae  with  four,  rarely  three,  segments;  third  abdominal  segment  usually 
with  less  than  six  annulets;  tenth  abdominal  tergum  with  or  without  caudal  protu- 
berances   29. 

29(32)  Abdominal  segments  1-7  on  ventro-meson  with  an  eversible  gland;  body  often  with 
numerous  conspicuous  setae,  setae  arising  from  distinct  tubercles;  antennae  with  four 
segments 30. 

30(31)  Body  with  numerous  conspicuous  multisetiferous  tubercles,  each  tubercle  bearing 
several  long  setae,  some  of  which  are  distinctly  longer  than  others;  third  abdominal 
segment  with  four  annulets,  annulet  1  with  a  transverse  row  of  setae,  annulets  2  and 
3  with  a  transverse  row  of  setiferous  tubercles;  tenth  abdominal  tergum  never  with 
caudal  protuberances  altho  with  numerous  long  setae;  setae  barbed  .  CLADIINAE. 

31(30)  Body  without  numerous  conspicuous  multisetiferous  tubercles,  if  tubercles  present, 
they  do  not  bear  several  long  setae  some  of  which  are  distinctly  longer  than  others; 
third  abdominal  segment  with  varying  number  of  annulets;  tenth  abdominal  tergum 
sometimes  with  caudal  protuberances;  setae  not  barbed NEMATINAE. 

32(29)  Abdominal  segments  1-7  on  ventro-meson  without  an  eversible  gland;  body  never 
conspicuously  setiferous;  antennae  with  three  or  four  segments;  third  abdominal 
segment  with  three  or  five  annulets 33. 

33(34)  Antennae  with  four  segments;  third  abdominal  segment  with  five  annulets;  abdom- 
inal segments  2-4  and  8  or  2-5  and  8  without  a  postsubspiracular  sucker-like  pro- 
tuberance  HOPLOCAMPINAE  (in  part). 

34(33)  Antennae  with  one  segment ;  third  abd  ominal  segment  with  three  annulets ;  abdominal 
segments  2-4  and  8  or  2-5  and  8  each  with  a  postsubspiracular  sucker-like  protuber- 
ance  ACORDULECERINAE. 


363]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  45 

35(26)  Anal  larvapods  united  on  the  meson  forming  a  single  protuberance;  antennae  with 
one  segment;  third  abdominal  segment  with  two  annulets;  prothorax  often  with 
dorsal  and  ventral  shields;  vertical  furrows  wanting;  head  and  body  depressed, 
glabrous SCOLIONEURINAE. 

36(25)    Larvapods  wanting  on  ultimate  segment;  vertical  furrows  wanting 37. 

37(38)  Antennae  with  three  segments;  third  abdominal  segment  with  four  annulets,  annulets 
2  and  3  setiferous;  tenth  abdominal  tergum  with  a  caudo-mesal  protuberance;  body 
not  depressed HOPLOCAMPINAE  (in  part). 

38(37)  Antennae  with  1-2  segments;  third  abdominal  segment  with  two  annulets,  annulets 
glabrous;  tenth  abdominal  tergum  without  a  caudo-mesal  protuberance;  body 
depressed FENUSINAE. 

39(24)  Thoracic  legs  with  3-4  or  6  segments;  larvapods  on  abdominal  segments  2-7  and  10 
or  2-6  and  10,  very  small 40. 

40(41)  Mesothoracic  and  meta thoracic  legs  with  six  segments;  prothoracic  legs  with  six 
segments;  larvapods  on  abdominal  segments  2-7  and  10  and  occasionally  with  a 
rudimentary  eighth  pair,  or  2-6  and  10;  body  dilated  laterad,  sublateral  lobe  pro- 
duced and  conspicuous,  often  with  numerous  setiferous  tubercles.  HYLOTOMINAE. 

41(40)  Mesothoracic  and  metathoracic  legs  with  three  segments;  prothoracic  legs  with 
four  segments;  larvapods  on  abdominal  segments  2-7  and  10  with  an  occasional 
rudimentary  eighth  pair;  body  not  dilated  laterad,  sublateral  lobe  not  produced 
and  conspicuous;  body  never  with  numerous  setiferous  tubercles  but  with  minute 
protuberances SCHIZOCERINAE. 

42(1)  Thoracic  legs  not  normal  in  form,  but  fleshy,  indistinctly  four-segmented,  tarsal 
claws  wanting;  larvapods  vestigial  on  abdominal  segments  2-8  and  10,  ultimate 

pair  united  on  the  meson,  forming  a  single  protuberance 

PHYLLOTOMINAE  (in  part) . 

Subfamily  Diprioninae 

Larvae  (Fig.  7)  moderately  large,  length  18-25  mm.;  body  cylindrical, 
somewhat  robust,  tapering  gradually  caudad;  segmentation  and  annula- 
tion  distinct;  third  abdominal  segment  with  six  annulets,  annulets  1,  2, 
and  4  or  2  and  4  with  setae  and  glandubae;  larvapods  on  abdominal 
segments  2-8  and  10,  close  together  on  the  meson;  thoracic  legs  normal, 
well  developed,  with  five  segments;  prothoracic  legs  distinctly  smaller  than 
other  legs;  color  of  body  usually  yellowish  or  greenish,  with  grayish,  or 
brownish  stripes  or  rows  of  black  spots;  antennae  with  three  segments,  seg- 
ments 1  and  2  minute,  flat,  irregular,  incomplete,  segment  3  erect,  peg-like, 
strongly  chitinized;  head  and  legs  usually  with  spinous,  stiff  setae;  glandu- 
bae prominent  and  numerous;  ventral  glands  wanting;  spiracles  not  winged; 
cuticle  microscopically  spinulate;  larvae  feed  on  conifers. 

The  subfamily  Diprioninae  is  represented  in  North  America  by  three 
genera,  Diprion,  Neodiprion,  and  Monoctenus.  The  Neartic  species 
formerly  placed  in  the  genus  Diprion  (Lophyrus)  are  placed  by  Rohwer 
(1918a)  in  Neodiprion.  Diprion  simile  Hartig  of  Europe  has  recently 
become  established  in  the  United  States.  With  the  exception  of  Mac- 
Gillivray,  systematists  agree  in  associating  the  genus  Monoctenus  with 
Diprion  and  its  allies. 


46  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [364 

The  three  genera  studied  can  be  separated  as  follows: 

1(2)  Body  large,  stout,  longer  than  24  mm.;  markings  mottled  with  dark  brown  and 
yellowish  irregular  spots,  without  brownish  stripes  or  black  spots;  setae  on  head 
small,  slender,  those  on  genae  similar  to  other  setae,  not  spinous;  head  blackish. 

Diprion  Schrank. 

2(1)  Body  smaller,  slender,  usually  shorter  than  24  mm.;  markings  not  mottled,  but  with 
brownish  longitudinal  stripes  or  rows  of  black  spots 3. 

3(4)      Third  abdominal  segment  with  annulets  1,  2  and  4  with  setae  and  glandubae;  setae 

on  head  stiff,  long,  spinous,  those  on  genae  often  very  large  and  spinous 

Neodiprion  Rohwer. 

4(3)  Third  abdominal  segment  with  annulets  2  and  4  with  setae  and  glandubae;  setae  on 
head  microscopic,  and  very  few  in  number Monoctenus  Dahlbom. 

Neodiprion  Rohwer 

Larvae  rather  large;  length  about  19-24  mm.;  body  slender,  with  longi- 
tudinal brownish  stripes  or  rows  of  black  spots  along  subdorsal,  supra- 
spiracular,  and  sometimes  subspiracular  lines;  head  round  in  contour, 
cephalic  and  caudal  margins  parallel  in  profile;  front  flattened,  subpenta- 
gonal,  as  high  as  wide;  ocularia  large;  antennaria  subequal  in  diameter  to 
ocularia,  their  own  diameter  apart;  lab  rum  semicircular,  with  small 
crescentic  median  emargination;  mandibles  sharply  dentate,  the  dextral 
with  four  dentes  and  the  sinistral  with  five;  maxillary  palpi  large,  four- 
segmented,  segments  1-3  ring-like,  successively  diminishing  in  diameter, 
segment  4  suddenly  and  distinctly  smaller  than  the  preceding  segment, 
conical,  bluntly  pointed;  galea  chitinized,  digit-like,  smaller  than  palpi; 
lacinia  thick,  lobate,  bearing  a  minute  triangular  blade-like  seta  on  ventro- 
mesal  angle,  a  stiff  seta  on  dorso-mesal  angle,  and  a  row  of  three  to  five 
minute  setae  on  the  oblique  cephalo-mesal  margin;  labial  palpi  normal, 
segment  2  usually  longest,  segment  3  conical,  suddenly  and  distinctly 
smaller  than  preceding  segment;  totaglossa  with  dorso-cephalic  depression 
on  the  meson  and  with  several  minute  sensory  pits;  parapharynx  distinct, 
linguiform,  constricted  dorsad  of  the  middle  by  a  pair  of  chitinized  pieces; 
thoracic  legs  well  developed,  normal  in  form,  usually  blackish,  segments 
strongly  chitinized,  coxae  largest,  trochanter  ring-like,  chitinized  on  the 
caudal  two-thirds,  with  a  whorl  of  setae,  distad  of  setae  membranous, 
femur  smaller  than  trochanter  in  diameter,  entirely  chitinized,  wider  than 
long  on  dorsal  aspect,  increasing  in  diameter  distad,  tibia  subequal  in  length 
to  femur  but  smaller  in  diameter,  tarsal  claws  small,  basal  portion  of  claw 
undeveloped,  all  segments  of  leg  membranous  on  the  ventral  aspect, 
prothoracic  legs  one-half  the  size  of  metalegs,  mesolegs  slightly  smaller 
than  the  latter;  third  abdominal  segment  with  annulation  formula,  2,  1, 
(3,  5,  6),  5;  spiracle  on  annulet  2,  annulets  1,  2  and  4  with  a  transverse 
row  of  slender,  cylindro-conical  glandubae,  annulet  2  with  a  few  micro- 
scopic setae;  substigmatal  and  surpedal  lobes  large,  with  several  glandubae 


365]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  47 

and  a  few  setae;  larvapods  well  developed,  distal  surface  incurved  mesad, 
rather  dilated,  not  pointed,  distance  between  the  pair  at  the  base  less 
than  the  length  of  larvapod,  venter  with  four  annulets;  tenth  abdominal 
tergum  gradually  convex,  with  glandubae;  anal  setae  numerous,  small; 
spiracles  elongate  and  oblong. 

SPECIES  OF  NEODIPRION 

1(10)  Head  black,  light  grayish  or  brownish,  never  uniformly  reddish  brown  or  orange; 
body  longitudinally  striped  or  spotted 2. 

2(3)  Body  with  four  longitudinal  rows  of  black  spots  along  subdorsal  and  supraspiracular 
lines;  tenth  abdominal  tergum  with  cephalic  two-thirds  entirely  black;  spots  on  each 
side  of  dorso-meson  elongate,  wider  at  cephalic  end;  spots  on  supraspiracular  line 
large,  subquadrate;  spots  onprothorax  obsolete;  body  yellowish  white;  length,  22  mm. ; 
on  Pinus;  Y-221,  G-573,  C-l,  1-4101 abbotii  Leach. 

3(2)  Body  without  four  longitudinal  rows  of  black  spots  along  the  subdorsal  and  supra- 
spiracular lines,  but  with  longitudinal  colored  bands  along  each  side  of  the  dorso- 
meson;  latus  with  longitudinal  row  of  independent  segmentally  arranged  blackish 
or  brownish  spots  or  with  continuous  brownish  bands 4. 

4(5)  Body  with  a  row  of  brownish  spots  along  supraspiracular  lines,  spots  segmentally 
arranged,  one  on  each  segment,  often  those  on  middle  segments  obsolete,  sometimes 
all  spots  obsolete;  tenth  abdominal  tergum  with  a  pair  of  large  blackish  or  brownish 
spots  which  are  all  sometimes  contiguous  on  meson;  subdorsal  bands  narrower  than 
the  distance  between  them;  larvapods  marked  faintly  along  pedal  line  when  supraspir- 
acular spots  are  distinct;  head  black;  length,  23  mm.;  G-1686-2,  -5.  Neodiprion  sp.  1. 

5(4)  Body  with  broad  longitudinal  bands  along  supraspiracular  lines,  instead  of  rows  of 
segmentarly  arranged  spots 6. 

6(7)  Subspiracular  lines  with  broad  brownish  bands;  head  black;  pedal  lines  also  marked 
brown;  tenth  abdominal  tergum  faintly  marked;  subdorsal  bands  much  wider  than 
the  distance  between  them;  these  bands  much  lighter  in  color  than  those  on  latus; 
body  dull  greenish;  length,  21  mm.;  on  spruce;  G-791 abietis  Harris. 

7(6)  Subspiracular  lines  without  brownish  bands;  head  light  brown,  brown,  or  pale 
creamy  yellow;  subdorsal  bands  very  narrow  or  very  wide;  pedal  lines  with  or 
without  bands 8. 

8(9)  Pedal  lines  with  distinct  brownish  bands;  tenth  abdominal  tergum  unmarked  except 
along  caudal  margin;  subdorsal  bands  very  much  wider  than  the  distance  between 
them,  lighter  in  color;  head  blackish  or  brownish  with  brown  marks  on  vertex  and 
front  or  pale  brown;  length,   19  mm.;  G-156 Neodiprion,  sp.  2. 

9(8)  Pedal  lines  without  distinct  brownish  bands;  tenth  abdominal  tergum  marked, 
entirely  concolorous  with  head;  subdorsal  bands  very  narrow,  usually  narrower  than 
the  distance  between  them;  head  light  brown  or  pale  creamy  white  with  vertex 

shaded  grayish;  length,  19  mm.;  G-1686-3,  -6,  -7 Neodiprion  sp.  3. 

10(1)      Head  reddish  brown  or  orange;  body  spotted;  subdorsal  and  supraspiracular  lines 

with  black  spots 11. 

11(12)  Subspiracular  and  pedal  lines  with  black  spots;  spots  on  subdorsal  lines  tapering 
caudad,  partly  broken  between  annulets;  spots  along  supraspiracular  lines  large, 
subquadrate;  spots  on  subspiracular  lines  smaller,  sometimes  very  small  but  never 
obsolete;  spots  on  pedal  lines  very  small,  sometimes  obsolete;  tenth  abdominal 
tergum  with  a  pair  of  large  black  spots  which  sometimes  fuse  on  the  meson;  length, 
25-28  mm.;  G-1554,  -1686-8,  -593,  C-cue-315,  C-Young-37 lecontei  Fitch. 


48  ILLINOIS  BIOLOGICAL  MONOGRAPHS  {366 

12(11)  Subspiracular  and  pedal  lines  without  black  spots;  spots  on  subdorsal  lines  small, 
often  not  distinctly  tapering  caudad;  tenth  abdominal  tergum  with  a  pair  of  large 
black  spots;  length,  20  mm.;  G-133 Neodiprion,  sp.  4. 

MONOCTENUS  DAHLBOM 

Larvae  rather  small;  length  about  15  mm.;  body  slender,  dorsum 
with  diffuse  brownish  shade  or  with  longitudinal  stripes;  third  abdominal 
segment  with  annulets  2  and  4  with  setae  and  glandubae;  head  as  in  Neo- 
diprion except  that  setae  are  minute  and  sparse;  clypeus  and  lab  rum  with 
two  setae  on  each  side;  labrum  with  small  crescentic  median  emargination; 
maxillary  palpi  large,  rather  slender,  segments  1-3  ring-like,  subequal  in 
length  but  successively  smaller  in  diameter;  galeae  and  laciniae  as  in  Neo- 
diprion; labial  palpi  rather  slender,  its  segments  subequal  in  length;  man- 
dible with  one  mandibular  seta;  antennae  with  segment  1  complete,  very 
narrow,  oval,  segment  2  flat,  incomplete,  irregular,  segment  3  peg-like, 
erect;  glandubae  conical,  distinct;  setae  microscopic;  sublateral  lobes  not 
well  developed;  annulation  typically  (1,  2),  (3,  4,  5,  6),  anal  setae  numer- 
ous, short,  and  minute;  telson  with  glandubae  obsolete. 

MacGillivray  established  in  1906  the  subfamily  Monocteninae  for 
the  genus  Monoctenus  associating  it  with  the  Cladiinae  and  Nematinae, 
thus  deviating  from  the  universal  practice  of  regarding  the  genus  Monoc- 
tenus as  a  member  of  the  subfamily  Diprioninae  or  its  equivalent.  On 
the  basis  of  the  venation,  MacGillivray's  contention  is  quite  justifiable, 
and  it  is  most  interesting  to  know  what  larval  characters  would  indicate 
in  regard  to  the  relationship  between  Monoctenus  and  Diprion  and  its 
allies.  Marlatt  (1887)  published  notes  on  the  immature  stages  of  Monoc- 
tenus unicolor  but  his  descriptions  do  not  touch  the  detailed  anatomy 
necessary  for  the  definition  of  the  genus.  Recently,  however,  I  was 
fortunate  enough,  thru  the  courtesy  of  Mr.  Rohwer,  to  examine  a  speci- 
men belonging  to  the  United  States  National  Museum  which  Rohwer 
considered  to  belong  to  a  new  species  of  Monoctenus.  A  careful  study 
of  this  larva  convinced  me  that  [so  far  as  this  species  is  concerned]  there 
are  no  essential  differences  between  the  larvae  of  Monoctenus  and  those 
of  the  typical  Diprioninae  to  justify  the  creation  of  a  new  subfamily. 
For  this  reason  I  have  followed  the  universal  practice  and  decided  to 
treat  Monoctenus  as  a  member  of  the  Diprioninae. 

Monoctenus  n.  sp.  Rohwer. —  Length,  14  mm.,  head-width  1.5  mm.; 
head  brownish;  body  on  dorsum  dorsad  of  spiracular  lines,  segments  of  legs, 
episternum  and  epimeron,  deep  brown;  glandubae  elongate,  conical, 
minute,  brownish  at  tip;  on  cedar. 

A  specimen  bearing  the  label  "5419  Sawfly  on  cedar,  Cadek,  Mo., 
June   10,    1892." 


367]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  49 

DlPRION  SCHRANK 

As  far  as  known,  only  one  species  is  represented  in  North  American 
fauna.  An  examination  of  D.  simile  shows  that  this  genus  is  not  very- 
different  from  the  other  genera  of  Diprioninae  but  may  be  separated  from 
them  by  the  characters  of  the  setae  and  coloration  of  the  head,  and  certain 
minor  points.  It  is  not  possible  to  characterize  the  genus  with  the  material 
at  hand. 

Diprion  simile  Hartig. — Body  robust,  length,  25  mm.;  latus  with  a  series 
of  yellowish  or  whitish  spots  on  a  uniformly  grayish  brown  background, 
dorso-meson  with  a  narrow  yellowish  stripe  bordered  on  each  side  by  an 
equally  narrow  grayish  brown  band;  dorso-lateral  lines  broadly  yellowish, 
interrupted  at  each  annulet  by  fine  transverse  lines;  supraspiracular 
lines  with  three  yellow  spots,  size  of  spots  increasing  caudad;  dorsad  of  these, 
three  smaller  spots  with  the  middle  one  largest  and  subequal  to  cephalic 
spot  of  supraspiracular  lines;  three  spots  on  subspiracular  lines,  the  middle 
one  being  the  largest;  pedal  lines  with  a  large  spot  on  each  segment; 
larvapod  with  a  brownish  spot;  tenth  abdominal  tergum  and  sternum 
marked  with  grayish;  the  tergum  with  a  deep  constriction  dorsad  of  suranal 
lobe;  head  setae  small,  slender,  hair-like,  never  spinous  or  stiff;  setae  on 
genae  similar  to  those  on  front,  never  stiff  and  spinous;  legs  with  femur 
sometimes  longer  than  wide  on  the  dorsal  aspect;  head  black;  body  yellow- 
ish gray,  mottled;  G. 

Subfamily  Emphytinae 
Larvae  (Fig.  8)  small  to  moderately  large,  usually  greenish,  sometimes 
striped;  body  cylindrical,  slender,  tapering  caudad;  segmentation  distinct, 
annulation  fine,  indistinct;  third  abdominal  segment  usually  with  six,  rarely 
seven,  annulets,  annulets  2  and  4  or  1,  3,  5  and  rarely  1,  3,  and  6  setiferous; 
head  greenish  or  brownish;  sometimes  with  spots  on  vertex  and  front; 
labrum  with  or  without  a  mesal  longitudinal  depression,  with  4-5  labral 
setae  on  each  side  of  the  meson;  clypeus  with  2  or  3  setae  on  each  side; 
mandibles  with  one  seta  rarely  with  two;  larvapods  on  abdominal  segments 
2-8  and  10,  well  developed,  usually  glabrous,  rarely  setiferous;  ventral 
glands  wanting;  glandubae  small,  conical,  on  annulets  1  and  3  or  rarely 
on  2  and  4;  tenth  abdominal  tergum  usually  setiferous  but  without  paired 
caudal  protuberances,  rarely  with  conspicuous  spines  on  the  caudal  margin, 
if  spines  present,  then  prothorax  and  mesothorax  on  dorsum  with  two  and 
one  protuberances  respectively;  antennae  elongate-conical,  with  five  seg- 
ments, segments  ring-like;  thoracic  legs  usually  normal  in  structure,  with 
femur  subequal  in  length  to  or  slightly  longer  than  tibia,  tibia  well  devel- 
oped and  normal,  femur  with  its  disto- ventral  angle  produced;  legs,  when 
modified,  short,  stout,  and  trochanter  obsolete;  mouth-parts  normal  in  form, 
spiracles  not  winged;  larvae  leaf -feeders. 


50  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [368 

The  Emphytinae  is  a  large  subfamily  embracing  a  number  of  genera 
and  numerous  species.  MacGillivray  considers  this  the  second  subfamily 
of  his  generalized  Tenthredinidae  and  places  it  between  the  Diprioninae 
and  Selandriinae.  The  larvae  of  this  subfamily  are  found  readily  and  in 
general  appearance  and  habitus  resemble  very  closely  the  larvae  of  the 
Selandriinae  and  Tenthredininae,  but  they  can  be  separated  by  the  number 
of  annulets,  which  in  this  subfamily,  with  the  exception  of  Hemitaxonus 
and  Epitaxonus,  is  six,  while  in  the  other  two  subfamilies  it  is  seven.  The 
two  genera  mentioned  are  characterized  by  the  presence  of  seven  annulets 
on  the  typical  abdominal  segment  and  also  by  the  setiferous  larvapods, 
thus  resembling  in  these  two  particulars  the  larvae  of  the  Selandriinae. 
It  is  of  interest  to  note  that  Rohwer  would  associate  Hemitaxonus  with 
such  genera  as  Selandria,  Eriocampoides,  etc.,  in  the  tribe  Selandriini  of 
his  subfamily  Selandriinae.  Middleton  (1915)  has  published  a  definition 
of  the  genus  Dimorphopteryx  together  with  a  key  for  the  separation  of 
three  species. 

The  writer  has  collected  a  large  number  of  larvae  belonging  to  this 
subfamily,  but  on  account  of  the  difficulty  of  breeding  adults  many 
species  remain  unidentified.  In  the  preparation  of  the  synoptic  key  to  the 
genera  and  in  discussions  following,  only  bred  or  otherwise  identified 
species  have  been  considered,  the  consequence  being  that  future  study  may 
require  much  modification  in  our  conception  of  the  various  genera  dealt 
with. 

GENERA  OF  EMPHYTINAE 

1(4)      Third  abdominal  segment  with  7  annulets;  larvapods  setiferous 2. 

2(3)  Larvapods  with  5-3-1  setae  on  cephalic,  lateral,  and  caudal  aspects  respectively; 
thoracic  legs  with  femur  longer  than  or  subequal  to  tibia;  labial  palpi  with  segment 

2  longer  than  segment  1 ;  maxillary  palpi  with  segments  subequal  in  length 

Hemitaxonus  Ashmead. 

3(2)  Larvapods  with  8-5-1  setae  on  cephalic,  lateral,  and  caudal  aspects  respectively; 
thoracic  legs  with  femur  shorter  than  tibia;  labial  palpi  with  segments  subequal  to 

each  other  in  length;  maxillary  palpi  with  segment  2  longer  than  segment  1 

Epitaxonus  MacGillivray. 

4(1)      Third  abdominal  segment  with  6  annulets;  larvapods  glabrous 5. 

5(26)  Tenth  abdominal  tergum  and  prothoracic  and  mesothoracic  tergites  without  con- 
spicuous fleshy  pointed  protuberances;  thoracic  legs  normal  in  form,  with  trochanters 
distinct 6. 

6(9)      Annulets  1, 2,  and  4  setiferous 7. 

7(8)  Antennae  with  segment  5  longest;  legs  with  femur  longer  than  tibia;  head  usually 
without  markings;  labial  palpi,  if  segments  not  subequal,  segment  2  longer  than 
segment  1 Empria  Lepeletier. 

8(7)  Antennae  with  segment  1  longest;  legs.with  femur  subequal  to  tibia;  head  usually 
with  markings;  labial  palpi,  if  segments  not  subequal,  segment  2  shorter  than  seg- 
ment 1 Parataxonus  MacGillivray 

9(6)      Annulets  2  and  4  setiferous 10. 


369]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  51 

10(11)  Clypeus  with  three  setae  on  each  side  of  meson;  mandibles  with  two  setae;  maxillae 
with  palpifer  produced  dorsad  as  a  triangular  lobe;  labrum  with  a  deep  median 

emargination  with  a  row  of  secondary  setae  caudad  of  the  emargination 

Eriocampa  Hartig. 

11(10)  Clypeus  with  two  setae  on  each  side  of  meson;  mandibles  with  one  seta;  maxillae 
with  palpifer  not  produced  dorsad  as  a  triangular  lobe;  labrum  without  a  deep 
median  emargination 12. 

12(13)    Thoracic  legs  with  trochanter  longer  than  tibia. . .  .Strongylogaslroidca  Ashmead. 

13(12)     Thoracic  legs  with  trochanter  distinctly  shorter  than  tibia 14. 

14(15)  Body  spotted  or  transversely  striped;  head  dorsad  of  ocellarae  entirely  blackish  or 
brownish;  very  large  and  robust  larvae Macremphytus  MacGillivray. 

15(14)  Body  never  spotted  or  transversely  striped;  head  dorsad  of  ocellarae  not  entirely 
blackish  or  brownish;  smaller  larvae 16. 

16(17)  Labial  palpi  with  segment  1  longer  than  segment  2;  legs  with  femur  always  longer 
than  tibia;  tibia  usually  twice  as  long  as  trochanter;  body  rather  robust;  head  not 

marked  distinctly  with  brown;  annulet  4  longest  on  third  abdominal  segment 

Monostegia  Costa. 

17(16)  Labial  palpi  with  segment  1  shorter  than  segment  2;  legs  with  femur  not  always 
longer  than  tibia;  tibia  always  more  than  twice  as  long  as  trochanter;  body  rather 
slender;  annulet  4  not  longest  on  third  abdominal  segment 18. 

18(19)     Head  entirely  pale,  no  markings;  legs  with  femur  longer  than  tibia;  body  on  dorsum 

not  shaded  darker  than  the  venter;  tenth  abdominal  tergum  not  marked 

Monosoma  MacGillivray. 

19(18)  Head  not  entirely  pale,  usually  with  brown  spots  or  markings;  legs  with  femur 
not  always  longer  than  tibia,  often  subequal;  body  on  dorsum  sometimes  shaded 
darker  than  the  venter;  tenth  abdominal  tergum  often  marked 20. 

20(21)  Legs  with  femur  always  longer  than  tibia;  tenth  abdominal  tergum  usually  marked ; 
body  on  dorsum  usually  shaded  darker  than  the  venter Emphytus  Klug. 

21(20)  Legs  with  femur  subequal  to  or  shorter  than  tibia;  tenth  abdominal  tergum  usually 
unmarked ;  body  on  dorsum  not  usually  shaded  darker  than  the  venter 22. 

22(23)    Tenth  abdominal  tergum  marked  with  a  spot;  body  on  dorsum  shaded  darker  than 

the  venter;  labial  palpi  with  segment  2  longer  than  segment  1 

Unitaxonus  MacGillivray. 

23(22)  Tenth  abdominal  tergum  unmarked;  body  on  dorsum  not  shaded  darker  than  the 
venter;  labial  palpi  with  segment  2  subequal  to  or  shorter  than  segment  1 24. 

24(25)    Labrum  with  a  distinct  median  depression Taxonus  Hartig. 

25(24)     Labrum  without  a  distinct  median  depression Phrontosoma  MacGillivray. 

26(5)  Tenth  abdominal  tergum  and  prothoracic  and  mesothoracic  tergites  with  con- 
spicuous fleshy  pointed  protuberances;  thoracic  legs  not  normal  in  form,  with 
trochanters  obsolete Dimorphopteryx  Ashmead. 

Subfamily  Selandriinae 

Larvae  (Fig.  9)  small  to  fairly  large,  length  18-26  mm.;  body  cylindrical 
and  gradually  tapering  caudad;  segmentation  and  annulation  distinct  and 
fine;  larvapods  on  abdominal  segments  2-8  and  10;  third  abdominal 
segment  with  seven  annulets,  annulets  1,  3,  and  5  setiferous,  annulets  3 
and  5  with  glandubae;  thoracic  legs  normal  in  form  except  tibia  sometimes 
very  minute;  body  uniformly  greenish,  without  colored  markings;  head 
with  or  without  brownish  spots;  antennae  with  five  segments,  long,  conical; 


52  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [370 

mouth-parts  normal  in  form,  well  developed,  palpi  large;  mandibles  with 
two  setae;  clypeus  with  three,  sometimes  four,  setae  on  each  side,  rarely 
with  two;  stipes  of  maxillae  with  triangular  cephalo-ventral  projection; 
glandubae  minute,  stalked;  spiracles  not  distinctly  winged;  larvapods 
setiferous,  with  about  ten  setae,  rarely  glabrous. 

The  Selandriinae  includes  a  limited  number  of  genera.  On  the  basis  of 
the  venation  this  subfamily  is  placed  next  to  the  Emphytinae  where 
practically  all  systematists  have  placed  it.  Rohwer's  conception  of  this 
subfamily  is  somewhat  different  from  that  of  MacGillivray  and  therefore 
he  differs  from  the  latter  in  the  disposition  of  some  of  the  genera.  For 
example,  Hemitaxonus  is  assigned  to  the  tribe  Selandriini  while  Mac- 
Gillivray placed  it,  together  with  Epitaxonus,  in  the  Emphytinae.  It  may 
be  said  that  the  larvae  of  these  two  genera  are  very  closely  related  to  the 
Selandriinae  and  differ  from  all  other  Emphytinae  in  the  typical  number 
of  annulets. 

GENERA  OF  SELANDRIINAE 

1(4)  Thoracic  legs  with  tibia  normal  in  form,  never  greatly  reduced,  usually  subequal 
in  length  to  femur;  larvapods  setiferous;  clypeus  with  three  or  four  setae  on  each 

side 2. 

2(3)  Tenth  abdominal  tergum  with  brown  spots;  larvapods  usually  with  ten  or  more 
setae;  clypeus  usually  with  three  and  often  four  setae  on  each  side;  labium  deep 
brown,  with  four  to  six  setae  on  each  side;  glandubae  slightly  longer  than  one-half  the 
length  of  adjacent  setae;  spiracles  not  winged;  larger  larvae;  length  more  than 
24  mm Tkrinax  Konow. 

3(2)  Tenth  abdominal  tergum  not  marked  with  brown  spots;  larvapods  usually  with  less 
than  ten  setae;  clypeus  with  three,  rarely  with  four,  setae  on  each  side;  labium  pale 
brown  or  whitish  with  three  to  six  setae;  glandubae  usually  subequal  in  length  to 
adjacent  setae;  spiracles  faintly  winged;  smaller  larvae;  length  less  than  24  mm. 

Strongylogaster  Dahlbom. 

4(1)  Thoracic  legs  with  tibia  reduced,  very  much  smaller  than  femur;  larvapods  glabrous; 
clypeus  with  two  setae  on  each  side Sdandria  Leach. 

Thrinax  Konow 

Larvae  comparatively  large,  long,  length  more  than  24  mm.;  body 
slender,  finely  annulate,  uniformly  greenish;  head  and  tenth  abdominal 
tergum  with  brown  markings;  thoracic  legs  normal,  tibia  and  femur 
cylindrical,  tapering  caudad,  subequal  in  length;  larvapods  with  about 
ten  setae,  distributed  as  follows:  4-5  on  cephalic  and  lateral  aspects  and 
one  on  caudal;  clypeus  usually  with  three  and  often  with  four  setae  on  each 
side;  labrum  with  four  to  six  setae  on  each  side,  deep  brown,  without 
median  longitudinal  depression;  glandubae  small,  very  short,  slightly  longer 
than  one-half  the  length  of  adjacent  setae;  spiracles  not  winged;  maxillary 
palpi  with  segments  2  and  4  subequal  in  length;  labial  palpi  with  segment  4 
longer  than  segment  3 ;  ninth  abdominal  tergum  with  six  annulets,  annulets 
1,  3,  and  5  setiferous,  annulet  6  a  little  shorter  than  the  second. 


371]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  53 

SPECIES  OF  THRINAX 

Head  pale  brown  with  vertex  marked  with  brown  on  dorsum  and  caudad  of  ocellarae, 
front  with  a  round  brown  spot  contiguous  to  ventral  apex  of  the  dorsal  marking  on 
the  vertex,  frontal  spot  not  reaching  the  fronto-clypeal  suture;  antennae,  mouth- 
parts,  femur,  tibia,  and  tarsal  claw  deep  brown;  tenth  abdominal  tergum  with  a 
pair  of  small  brown  spots;  annulation  formula,  1,  (5,  4,  3),  2,  (6,  7);  antennae,  5,  4, 
3, 2, 1 ;  labial  palpi  with  distal  two  segments  subequal;  legs  with  trochanter,  femur,  and 
tibia  with  lengths  to  each  other  as  12,  15,  and  16  respectively;  tarsal  claws  with  the 
proximal  portion  shorter  than  the  distal  narrow  curved  portion;  length  26  mm.; 

width  of  head  2  mm.;  on  fern;  M-18 impressatus  Provancher. 

Head  pale  brown  with  vertex  marked  with  brown  on  dorsum  and  caudad  of  ocellarae, 
front  with  a  subquadrate  spot  contiguous  to  the  ventral  apex  of  dorsal  marking  of  the 
vertex,  frontal  spot  reaching  the  fronto-clypeal  suture;  antennae,  labrum,  mouth- 
parts,  femur,  tibia,  and  tarsal  claw  deep  brown;  tenth  abdominal  tergum  with  a 
pair  of  large  brown  spots;  annulation,  1(5,  4,  3,  1),  (6,  7);  antennae,  5,  4,  1,  3,  2; 
labial  palpi  with  distal  segment  longer  than  the  preceding;  legs  with  trochanter, 
femur,  and  tibia  with  lengths  to  each  other  as  12, 15  and  16  respectively;  tarsal  claws 
with  the  proximal  portion  as  long  as  the  distal  curved  portion;  length  25  mm.; 
width  of  head,  2  mm.;  on  fem;  Y-20-3-1,  -20-1 pulatus  MacGillivray. 

Strongylogaster  Dahlbom 

Larvae  small  comparatively  speaking,  length  less  than  24  mm. ;  body 
slender,  finely  annulate,  uniformly  green;  head  pale  or  light  brown  or 
sometimes  with  a  few  spots;  tenth  abdominal  tergum  never  distinctly 
marked;  larvapods  usually  with  less  than  ten  setae;  thoracic  legs  normal  in 
form,  femur  and  tibia  subequal  to  each  other  or  one  longer  than  the  other; 
labrum  pale  brown  or  whitish,  with  three  to  six  setae  on  each  side;  glandu- 
bae  usually  subequal  in  length  to  adjacent  setae;  spiracles  often  faintly 
winged. 

SPECIES  OF  STRONGYLOGASTER 

1(2)  Head  with  blackish  brown  markings,  vertex  with  a  pair  of  diverging  spots  over  the 
vertical  furrows  directed  toward  ocellarae  and  a  spot  caudad  of  each  ocellara; 
vertical  markings  sometimes  faint,  sometimes  very  distinct  and  large,  merging  into  a 
continuous  vertical  marking;  front  never  with  spot;  antennae,  labrum,  and  mouth- 
parts  light  brown;  tenth  abdominal  tergum  usually  without  markings,  rarely  with  a 
pair  of  faint  spots;  annulation,  1, 4,  (2,3,  5),  (6,  7,) ;  antennae,  1,  5,  (2, 3, 4) ;  maxillary 
palpi,  2,  (1, 4),  3;  labial  palpi  with  two  distal  segments  equal  in  length  to  each  other, 
shorter  than  distal  segment  of  maxillary  palpi;  labrum  with  three  or  four  setae  on 
each  side;  mandible  with  two,  rarely  three,  setae;  legs  with  trochanter,  femur,  and 
tibia  with  lengths  to  each  other  as  10,  10,  and  12  respectively;  uropods  with  about 
eight  or  nine  setae,  five  on  cephalic,  3-4  on  lateral,  and  one  on  caudal  aspect;  glandu- 
bae  long,  slender,  subequal  in  length  to  adjacent  setae;  spiracles  not  winged;  length 
18  mm.;  width  of  head  1.8  mm.;  on  Pteris  aquilina;  Y-21 annulosus  Norton. 

2(1)      Head  without  blackish  brown  markings,  uniformly  pale  brown 3. 

3(4)  Trochanter  distinctly  shorter  than  femur;  labial  palpi  with  distal  segment  as  long 
as  the  preceding  segment;  head  uniformly  pale;  body  and  legs  uniformly  green 
without  markings;  annulation,  1,  (3,  4,  5),  (6,  7,  2);  antennae  slender,  5,  1,  (4,  3,  2); 
maxillary  palpi,  (2,  1),  (4,  3),  distal  segment  longer  than  that  of  labial  palpi;  labrum 


54  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (372 

and  clypeus  with  four  and  three  setae  respectively  on  each  side;  larvapods  with  about 
6-8  setae,  4-5  on  cephalic,  2-3  on  lateral  aspect;  glandubae  subequal  in  length  to 
adjacent  setae;  spiracles  with  faint  brown  wings;  thoracic  legs  with  trochanter,  femur, 
and  tibia  with  lengths  to  each  other  as  8,  13,  and  15  respectively;  length,  19  mm.; 

width  of  head,  1.6  mm.;  on  Pteris  aquilina;  Y-168-4 tacitus  Say. 

4(3)  Trochanter  not  distinctly  shorter  than  femur;  labial  palpi  with  distal  segment  shorter 
than  the  preceding  segment;  head  uniformly  pale,  rarely  with  a  pair  of  faint  spots  on 
dorsal  part  of  vertex;  body  uniformly  green;  legs  distad  of  trochanter  brownish; 
annulation,  1,  (5, 4,  3),  (2, 6,  7);  antennae,  slender,  conical,  (5, 1),  4,  (2,  3);  maxillary 
palpi,  2,  (4, 1),  3,  distal  segment  subequal  to  that  of  labial  palpi;  labrum  and  clypeus 
with  four  and  three  setae  respectively  on  each  side;  thoracic  legs  with  trochanter  little 
shorter  than  femur,  tibia  usually  almost  as  long  as  femur;  length,  21-23  mm.;  width 
of  head,  1.8  mm.;  on  Pteris  aquilina ;  Y-18-1,  M-32  (in  part),  M-86.  politus  Provancher. 

Selandria  Leach 

Larvae  comparatively  small,  length  less  than  24  mm.,  usually  about 
15  mm.;  body  slender,  finely  annulate;  head  pale;  body  green;  tenth 
abdominal  tergum  unmarked;  larvapods  glabrous;  legs  very  short,  with 
tibia  conspicuously  reduced  in  size,  femur  distinctly  dilated  at  distal 
end,  bearing  rudimentary  tibia  on  dorsal  margin;  clypeus  with  two  setae  on 
each  side;  mandible  with  two  setae;  labrum  with  three  setae  on  each  side; 
glandubae  very  small;  spiracles  not  winged. 

Selandria flavipes  Norton. — Legs  with  trochanter  ring-like,  femur  dilated 
at  distal  end,  with  ventro-mesal  projection  only  slightly  narrower  in 
diameter  than  trochanter;  tibia  very  small,  much  smaller  in  diameter  than 
femur,  appearing  as  if  surrounded  by  fleshy  part  of  the  latter,  deep  brown 
in  color;  trochanter,  femur,  and  tibia  with  lengths  to  each  other  as  7,  11, 
and  6,  respectively;  annulation,  1,  4,  2,  (3,  5,  6,  7);  antennae  slender,  coni- 
cal, 5,  (1,  2,  4,  3);  maxillary  palpi,  (4,  1,  2),  3;  labial  palpi  with  distal 
segment  subequal  in  length  to  segment  1,  longer  than  distal  segment  of 
maxillary  palpi;  length,  15  mm.;  width  of  head  1.3  mm.;  on  Pteris  aqui- 
lina: Y-168,  M-70,  C-S.f. 

Subfamily  Dolerinae 

Larvae  (Fig.  10)  moderately  large,  length,  15-25  mm.;  body  slender, 
cylindrical,  tapering  uniformly  and  gradually  caudad,  either  uniformly 
greenish  or  brownish,  or  dorsum  colored  darker  than  venter,  never  with 
bright  and  distinct  patterns;  segmentation  and  annulation  distinct;  third 
abdominal  segment  with  six  annulets,  annulets  2  and  4  on  dorsum  seti- 
ferous  and  with  glandubae;  larvapods  on  abdominal  segments  2-8  and  10; 
thoracic  legs  well  developed;  head  large,  as  wide  as  thorax  or  nearly  so; 
vertical  furrows  distinct;  antennae  five-segmented,  conical;  labrum 
distinctly  asymmetrical,  dextral  part  larger  than  sinistral;  head,  legs, 
larvapods,  tenth  abdominal  tergum,  and  sternum  moderately  setiferous; 
glandubae  present;  spiracles  not  winged;  cuticle  distinctly,  uniformly,  micro- 


373]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  55 

scopically  verrucose  on  the  dorsum  and  latus  between  spiracular  lines;  on 
monocotyledonous  plants. 

The  Dolerinae  is  a  well-defined  subfamily  with  a  distinct  habitus 
and  is  closely  allied  to  the  Emphytinae  and  Selandriinae.  The  most 
important  adult  character  for  differentiating  the  group  from  other  sub- 
families of  the  generalized  Tenthredinidae  is  the  coalescence  of  the  cells 
R4  and  R5  due  to  the  atrophy  of  the  free  part  of  the  vein  R5.  The  sub- 
family contains  two  genera,  the  old  genus  Dolerus  and  the  recently  de- 
scribed genus  Loderus.  Leach  separated,  under  the  name  of  Dosytheus, 
all  those  species  having  certain  antennal  peculiarities  and,  according 
to  Stephens,  also  having  bright  colors  on  the  abdomen.  This  differen- 
tiation was  considered  invalid  by  Hartig  and  his  view  was  endorsed  by 
Norton  and  Cameron.  Norton  described  a  species  under  the  name  of 
Dorytheus  apricus  var.  albifrons  which  is  now  placed  in  the  genus  Loderus. 
The  monobasic  genus  Pelmatopus  of  Hartig,  based  on  P.  minutus,  is  now 
considered  as  congeneric  with  Dolerus.  Since  the  larvae  of  Loderus  are 
unknown,  the  genus  Dolerus  alone  is  considered  here. 

Dolerus  Jurine 

Head  viewed  from  cephalic  aspect  circular  in  contour  in  mature 
specimens,  epicranium  semiglobose,  front  distinctly  flattened;  mouth- 
parts  directed  caudo-ventrad;  antennaria  never  circular,  with  obtuse 
corners  at  the  angles  of  their  dorsal  side;  antennae  with  formula,  5,  (3,  4, 
2),  1,  distal  segment  conical,  apex  less  chitinized  and  obtusely  rounded, 
never  sharply  pointed,  segments  2-5  well  chitinized,  segment  1  narrow  but 
distinctly  larger  in  diameter  than  distal  segments;  front  distinctly  wider 
than  high;  labrum  asymmetrical,  dextral  part  always  larger  than  sinistral 
or  with  pointed  ventro-mesal  angle;  mandible  very  thick,  large,  dextral 
with  four  distadentes  and  one  curved  sharp  proxadentis,  sinistral  with 
four  distadentes  and  mesal  surface  deeply  emarginate;  parapharynx  with 
apex  dilated  and  chitinized;  maxillary  palpi,  galea,  lacinia,  and  labial 
palpi  normal  in  structure  and  well  chitinized;  thoracic  legs  with  femur 
often  produced  papilla-like  on  its  disto- ventral  angle,  tibia  long,  cylindrical, 
tapering  uniformly  distad,  distinctly  longer  than  femur,  tarsal  claw 
rather  slender  and  straight;  abdominal  segments  with  six  annulets,  typical 
formula,  (1,  2),  3,  4,  (5,  6),  1  =5+6;  spiracles  on  annulet  2;  annulets  2  and 
4  with  conical  glandubae  and  tiny  cylindrical  truncate  setae  with  large 
calices;  tenth  abdominal  tergum  semiglobose,  anal  setae  numerous;  ventral 
glands  never  present. 

The  genus  Dolerus  is  represented  in  North  America  by  more  than 
thirty  species  but  none  of  them  had  been  identified  in  the  immature  stages 
until  the  writer  reared  the  adult  of  D.  similis  Nort.  at  Ithaca,  N.  Y.    The 


56  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [374 

larvae  of  this  genus  are  easily  obtained  and  readily  identified  because  of 
the  marked  asymmetry  of  the  labrum. 

The  following  key  will  serve  to  separate  the  species  studied: 

SPECIES  OF  DOLERUS 

1(6)  Head  uniformly  pale,  creamy,  or  pale  brown;  body  uniformly  whitish  or  greenish, 
without  distinct  dorsal  band 2. 

2(3)  Body  with  small  black  spots  on  each  segment  along  supraspiracular  and  pedal  lines; 
head  pale  brownish  yellow;  spots  on  ninth  abdominal  segment  much  smaller  than 
preceding  ones;  length,  25  mm.;  on  wheat  and  grasses;  Y-l  17-1-1,  G-d-1.  Dolerus  sp.  1. 

3(2)  Body  without  small  black  spots  on  each  segment  along  supraspiracular  and  pedal 
lines;  head  creamy;  length  less  than  25  mm 4. 

4(5)  Distance  between  antennaria  and  mandibularia  subequal  to  distance  between  anten- 
naria  and  ocularium;  length,  20  mm.;  on  Carex  trichocarpa;  Y-24-5-2,  -145-1(?),-147. 

Dolerus  sp.  2. 

5(4)  Distance  between  antennaria  and  mandibularia  twice  or  more  than  twice  the  distance 
between  antennaria  and  ocularium;  length  of  prothoracic  spiracles  in  relation  to 
vertical  diameter  of  antennaria  variable;  femur  with  or  without  disto-ventral  pro- 
jection; front  with  or  without  pale  brown  spot;  length  18-20  mm.;  on  grasses,  sedge, 
timothy;  Y-29- 11,-32-1,  M-7,  H,-41-l,-63,-225 Dolerus  sp.  3" 

6(1)  Head  spotted,  banded,  or  distinctly  brown,  black,  or  purple;  body  uniformly  longi- 
tudinally banded  or  striped  on  dorsum,  especially  along  dorso-lateral  lines,  rarely 
uniformly  whitish  or  greenish 7. 

7(8)  Head  with  a  distinct  blackish  semicircular  band  extending  from  gena  to  gena  dorsad 
of  front  and  involving  ocellarae;  body  with  a  very  fine  brownish  line  along  latero- 
dorsal  lines,  more  distinct  on  caudal  segments;  thoracic  legs  uniformly  pale;  length, 
15  mm.;  on  grasses;  Y-41-l-l,-41-2,-41-3,-8.47(?)    M-41,-235 Dolerus  sp.  4. 

8(7)  Head  without  distinct  blackish  semicircular  band,  but  with  spots  or  dark-colored 
areas;  thoracic  legs  with  femur,  tibia,  and  claws  brown,  not  concolorous  with  coxa.  .9. 

9(12)     Head  pale  brown,  vertex  with  brown  spots;  body  uniformly  whitish  or  with  light 

dorsal  band .. 10. 

10(11)  Vertex  with  two  small  spots,  one  dorso-mesad  of  each  vertical  furrow,  variable  in 
size  but  never  linear  along  the  furrow;  body  uniformly  whitish  or  creamy;  length. 

21  mm.;  on  Carpinus and  Pteris  aquilina  (both doubtful);  Y-74-1-1,  M-82 

Dolerus  sp.  5. 

11(10)     Vertex  with  one  minute  spot  at  the  origin  of  epicranial  stem;  light  brown  spot  along 

epicranial  suture  to  ocellarae;  body  with  dorsal  band  lighter  on  dorso-meson  and 

darker  on  supraspiracular  lines,  more  distinct  on  caudal  segments;  length,  15  mm.; 

on  Equisetum    arvense;    Y-145-2 Dolerus  sp.  6. 

12(9)  Head  brownish  with  purplish  or  brownish  markings  on  vertex,  only  rarely  light 
brown  or  yellowish,  then  vertical  furrows  with  brownish  streaks;  body  with  distinct 

dorsal  band 13. 

13(14)  Head  deep  purplish  black  with  following  parts  whitish:  proximal  half  of  epicranial 
stem,  vertical  furrows,  vertex  caudad  of  ocellarae  to  the  middle  of  epicranial  stem 
very  narrowly,  epicranial  arms,  clypeus,  and  labrum;  dorsal  band  lighter  on  dorso- 
meson;  pedal  lines  with  a  row  of  grayish  patches;  legs  with  femora  without  disto- 
ventral  projection;  length,  19  mm. ;  on  Equisetum  arvense;  Y- 146-1-2 . .  si  mil  is  Norton. 
14(13)  Head  usually  brownish  or  yellowish,  vertex  deeply  brown,  at  least  along  vertical 
furrows;  typically  pale  on  vertex  ventrad  of  vertical  furrows  and  caudad  of  ocellarae; 
front  with  or  without  brownish  spot;  tenth  abdominal  tergum  on  both  sides  usually 


375]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  57 

more  brownish  than  on  meson;  legs  with  femora  without  disto- ventral  projection; 
length,  20-23  mm.;  on  sedges;  Y-28-l,-27-l-l,-30,-210-l-8.32(?)-l-l,  M-7,-8,-9,-35, 
-64,-193,G-d-3. Dolerus  sp.  7. 

Subfamily  Phyllotominae 

Larvae  (Fig.  11-12)  small,  length  usually  less  than  15  mm.;  body  sub- 
cylindrical  or  depressed,  without  colored  patterns;  larvapods  on  abdominal 
segment  with  two  or  six  annulets;  antennae  with  3-4  or  5  segments; 
thoracic  legs  with  four  segments,  short,  stubby,  with  or  without  tarsal 
claws. 

The  Phyllotominae  can  be  divided  into  two  distinct  tribes  on  the  basis 
of  the  larval  characters.    The  tribes  can  be  separated  as  follows: 

Thoracic  legs  with  tarsal  claws;  head  normal  in  form,  not  depressed;  third  abdominal 

segment  with  six  annulets;  external  feeders Phyllotomini. 

Thoracic  legs  without  tarsal  claws;  head  depressed;  third  abdominal  segment  with 
two  annulets;  leaf-miners Phlebatrophini. 

The  Phyllotominae  is  a  distinct  group  and  includes  four  genera,  Phyl- 
lotoma,  Caliroa,  Endelomyia,  and  Phlebatrophia.  In  the  Nearctic  region, 
the  last  three  genera  are  represented  by  a  limited  number  of  species. 
MacGillivray  considered  this  family  as  one  of  the  five  generalized  sub- 
families of  the  Tenthredinidae,  quite  apart  from  the  Fenusinae  and 
Scolioneurinae,  but  Rohwer  would  associate  them  in  his  subfamily  Mes- 
sinae  while  Konow  would  include  Hoplocampinae  and  Phyllotominae 
in  his  tribe  Hoplocampides.  The  subfamily  is  divisible  into  two  distinct 
groups  according  to  the  characters  of  the  larvae.  The  remarkable  speciali- 
zation of  structures  due  to  the  leaf-mining  habit  of  the  larva  in  one  genus 
where  specialization  has  proceeded  much  further  than  in  any  of  the  other 
leaf-miners,  makes  the  division  of  the  subfamily  into  two  tribes  desirable. 

Tribe  Phyllotomini 

Body  practically  subcylindrical,  thorax  distinctly  swollen,  some- 
times distinctly  tadpole-like,  tapering  caudad;  segmentation  and  annu- 
lation  indistinct,  fine,  subequal  in  length;  third  abdominal  segment 
with  six  annulets,  annulets  2  and  4  microscopically  and  sparsely  setiferous 
or  minutely  tuberculate;  tenth  abdominal  tergum  with  or  without  tubercles; 
thoracic  legs  as  long  as  head  is  wide,  subequal  in  size,  short,  modified,  with 
four  segments,  stubby,  with  distinct  tarsal  claws,  coxa  conical,  femur 
cylindrical,  as  long  as  wide,  tibia  convex,  wider  than  long,  distal  segment 
very  minute,  with  sharp  incurved  claw;  larvapods  on  abdominal  segment 
2-8  normal  in  form,  glabrous,  distal  lobe  with  a  minute  point  on  its  cephalo- 
ventral  angle;  ultimate  segment  with  a  pair  of  normal  larvapods  or  without 
any;  head  small,  normal,  not  depressed,  sparsely  setiferous,  longer  than 


58  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [376 

wide,  slightly  pointed  at  dorsal  apex;  mouth  directed  slightly  ventro-caudad; 
antennae  with  four  or  five  segments,  slender,  elongate,  conical,  or  sub- 
conical;  mouth-parts  normal  in  form;  spiracles  with  or  without  wings; 
ventral  glands  wanting;  prothoracic  glands  sometimes  present;  glandubae 
present,  conical,  tuberculate  or  sessile;  cuticle  usually  microscopically 
verrucose;  larvae  in  life  sometimes  distinctly  slimy;  subgregarious;  leaf- 
skeletonizers. 

GENERA  OF  PHYLLOTOMINI 

Body  without  minute  tubercles,  tadpole-like,  slimy;  glandubae  sessile Caliroa  Costa. 

Body  with  minute  tubercles,  not  tadpole-like,  not  slimy;  glandubae  conical,  tuberculate. 

Enddomyia  Ashmead, 

Endelomyia  Ashmead 

Larvae  small,  length  less  than  15  mm.,  greenish  yellow;  body  sub- 
cylindrical,  apparently  almost  glabrous,  not  tadpole-like,  thorax 
thickened,  tapering  caudad;  third  abdominal  segment  with  six  annulets, 
annulets  2  and  4  tuberculate;  tenth  abdominal  tergum  with  eight  to  ten 
conical  tubercles  arranged  approximately  in  three  transverse  rows;  suranal 
and  subanal  lobes  with  several  rather  long  stiff  setae;  thoracic  legs  with 
distinct  tarsal  claws;  larvapods  on  ultimate  segment  normal  in  form, 
separated;  antennae  with  five  segments,  slender,  elongate-conical;  mandi- 
bles with  dentes;  spiracles  not  winged;  spiracles  on  sublateral  lines;  pro- 
thoracic  glands  wanting;  glandubae  conical,  tuberculate;  body  not  slimy. 

Endelomyia  aethiops  Fabricius. — Length,  13  mm. ;  width  of  head,  1.2  mm. ; 
head  light  brown;  mouth-parts,  labrum,  and  tarsal  claws  deep  brown;  body 
greenish  yellow  to  yellowish  white;  tubercles  concolorous  with  body; 
typical  tubercular  formula  on  pro  thorax:  3-6  on  first  annulet,  2-3  on  pro- 
subspiracular  lobe,  2-5  on  annulet  2;  third  abdominal  segment  with  2  and 
3  tubercles  on  annulets  2  and  4  respectively,  1  on  annulet  3  near  the  spiracle, 
1  each  on  subspiracular  and  surpedal  lobe;  annulation,  1,  2,  3,  4,  (5,  6); 
antennae,  1,  (2,  3,  4),  5;  maxillary  palpi,  (1,  2,  3),  4;  labial  palpi,  1,  2,  or 
(1,  2);  subgregarious;  on  Rosa;  Y-2,  M-127. 

Caliroa  Costa 

Larvae  small,  length  6-12  mm.,  whitish;  body  distinctly  tadpole-like; 
thorax  conspicuously  swollen,  rounded  on  dorsum  and  flattened  on  venter; 
tapering  distinctly  caudad;  third  abdominal  segment  with  six  indistinct 
annulets,  annulets  2  and  4  with  a  few  glandubae;  tenth  abdominal  tergum 
without  tubercles;  suranal  and  subanal  lobes  often  with  a  number  of  stiff 
rather  long  setae;  thoracic  legs  with  distinct  tarsal  claws;  larvapods  on 
ultimate  segment  obsolete,  their  position  indicated  by  a  small  median 
swelling;  antennae  with  four  segments,  rather  thick,  elongate,  distal 
segment  microscopic;  mandibles  with  dentes;  spiracles  usually  winged; 


377]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  59 

spiracular  line  abnormally  low  in  position,  coinciding  with  latero-ventral 
line;  prothoracic  glands  present,  large,  triangular,  fleshy,  attached  cephalo- 
mesad  of  prothoracic  legs;  glandubae  sessile; 

SPECIES  OF  CALIROA 

1(2)  Anal  setae  not  all  of  same  type  and  length,  longer  ones  arising  from  minute  but 
distinct  tubercles,  brown,  apparently  barbed,  curved  at  tips,  as  long  as  labrum, 
ten  to  twelve  in  number,  arranged  in  a  transverse  row  on  suranal  and  subanal  lobe; 
spiracles  distinctly  winged,  brown;  clypeus  light  brown;  head  deep  brown;  thoracic 
legs  and  antennae  deep  brown;  smaller  setae  on  anal  area  normal  in  form,  much 
shorter  than  the  long  barbed  ones,  scattered  beyond  the  transverse  rows;  lengths  of 
front,  clypeus,  labrum,  and  width  of  labrum  to  each  other  as  23,  10,  8  and  12  respec- 
tively; length  of  body,  11  mm.;  width  of  head,  1  mm.;  on  cherry,  plum,  Crataegus; 
Y-209,  M-260,-249,-115,  C-551,-552 cerasi  Linnaeus. 

2(1)  Anal  setae  all  of  same  type  and  length,  none  arising  from  distinct  tubercles  and 
barbed,  all  of  normal  type,  much  shorter  than  labrum;  spiracles  usually  not  winged .  3. 

3(8)  Head  blackish,  deep  brown,  or  brownish;  legs  brownish  in  part,  not  concolorous  with 
body 4. 

4(7)      Head  blackish  or  dark  brownish 5. 

5(6)  Head  black  or  dark  brownish  black;  anal  setae  scattered,  pale,  subequal  in  length, 
about  three-fifths  as  long  as  labrum;  prothoracic  legs  distinctly  lighter  in  color  than 
other  legs,  which  are  brownish;  spiracles  of  cephalic  segments  faintly  winged ;  clypeus 
whitish;  lengths  of  front,  clypeus,  labrum,  and  width  of  labrum  to  each  other  as 
22,  9,  8,  and  11,  respectively;  length  of  body,  10.5  mm.;  width  of  head,  1  mm.;  on 
oak;  M-157,-200,-245,  G-553c,  Y-mck Caliroa  sp.   1. 

6(5)  Head  deep  brown;  anal  setae  scattered,  subequal  in  length;  prothoracic  legs  higher  in 
color  than  other  legs;  spiracles  never  winged;  anal  setae  about  one-third  as  long  as 
labrum;  clypeus  pale  brown;  lengths  of  front,  clypeus,  labrum,  and  width  of  labrum 
to  each  other  as  18,  10,  8,  and  11  respectively;  length  of  body  6  mm.;  width  of  head, 
.9  mm. ;  on  wild  cherry;  C obsoleta  Norton. 

7(4)  Head  brownish  or  light  brown;  all  legs  pale  brownish;  anal  setae  scattered,  subequal 
in  length,  about  one-third  as  long  as  labrum;  clypeus  pale  brown;  lengths  of  front, 
clypeus,  labrum,  and  width  of  labrum  to  each  other  as  10,  9  ,7,  and  11,  respectively; 
length  of  body,  8  mm.;  width  of  head  1  mm.;  on  white  oak  and  Crataegus;  C-7, 
M-230 quercus-alba  Norton. 

8(3)  Head  pale  brown  or  whitish;  legs  whitish,  concolorous  with  body;  spiracles  not 
winged;  anal  setae  scattered,  subequal  in  length,  about  three-fifths  as  long  as  labrum; 
lengths  of  front,  clypeus,  labrum,  and  width  of  labrum  to  each  other  as  21,  9,  7,  and 
10,  respectively;  length  of  body,  10.5  mm.;  width  of  head,  1  mm.;  Y-121,  G-553c, 
M-143,-201,-231,-236-242 quercus-coccinea  Dyar. 

Tribe  Phlebatrophini 

Body  viewed  from  the  side  distinctly  depressed,  venter  flattened, 
thorax  thickened,  broadest  on  mesothorax,  prothorax  declivous  cephalad, 
caudal  segments  distinctly  tapering;  segmentation  and  annulation  distinct; 
third  abdominal  segment  with  two  annulets,  annulet  2  sparsely  and  incon- 
spicuously setiferous;  tenth  abdominal  tergum  without  tubercles;  tenth 
sternum  small;  thoracic  legs  modified,  fleshy,  indistinctly  four-segmented, 


60  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [378 

tapering  to  distal  end,  distal  segment  microscopic,  mamma-like,  without 
tarsal  claw;  larvapods  vestigial,  located  on  abdominal  segments  2-8  and  10, 
anal  larvapods  united  on  the  meson,  forming  a  single  sucker-like  pro- 
tuberance; head  distinctly  depressed,  pointed,  sub  triangular  in  contour, 
partly  overlapped  by  protruding  pro  thorax;  mouth  directed  cephalad; 
vertical  furrows  obsolete;  antennae  with  3-4  segments,  segments  1  and  2 
large  and  conical,  segments  3  and  4  subcylindrical  and  much  smaller  and 
less  in  diameter  than  proximal  segments;  mouth-parts  modified,  mandibles 
slender,  sharply  pointed,  without  dentes,  blade-like;  labium  flattened  and 
large;  spiracles  not  winged;  ventral  and  prothoracic  glands  wanting; 
glandubae  obsolete;  body  not  slimy;  leaf-miners. 

Phlebatrophia  MacGillivray 

Larvae  very  small,  whitish;  length  less  than  10  mm.;  body  distinctly 
depressed,  tapering  much  caudad,  broadest  on  mesothorax,  prothorax 
declivous  cephalad;  lateral  lobes  somewhat  prominent;  tenth  abdom- 
inal tergum  convex,  almost  glabrous,  about  half  as  wide  as  mesothorax; 
suranal  and  subanal  lobes  semiglabrous;  third  abdominal  segment  with 
two  annulets,  caudal  annulet  about  four  times  as  long  as  the  cephalic, 
microscopically  and  sparsely  setiferous;  thoracic  legs  fleshy,  tarsal  claws 
wanting;  larvapods  rudimentary;  ocularia  protruding,  located  laterad 
of  antennariae;  epicranial  suture  in  part  obsolete;  spiracles  not  winged; 
spiracular  line  normal  in  position;  maxillary  palpi  with  four  segments, 
labial  palpi  with  two  segments;  totaglossa  roundly  protruding;  stipes 
elongate,  subgalea  long,  slender,  with  distinct  chitinized  carinae;  labrum 
flattened;  mandibles  slender,  sharply  pointed,  without  dentes,  blade-like; 
leaf-miners. 

Phlebatrophia  mathesoni  MacGillivray. — Length,  7  mm. ;  width  of  head, 
1  mm.;  mesothorax,  2.4  mm.  wide;  head  light  brown,  mandibles  and 
carinae  of  subgalae  deep  brown;  maxillary  palpi  typically  2,  1,  3,  4,  distal 
segment  very  minute;  antennae  with  proximal  segment  or  segments 
larger  in  diameter  and  fleshy,  conical,  two  distal  segments  together  smaller 
and  shorter  than  the  other  two  segments,  but  longer  than  labial  palpi; 
distal  segment  of  labial  palpus  very  minute;  leaf-miners  of  birch;  C  and  G. 

Subfamily  Tenthredininae 

Larvae  (Fig.  13)  of  medium  to  rather  large  size;  body  cylindrical, 
slender,  tapering  uniformly  and  gradually  caudad;  segmentation  and 
annulation  distinct,  fine;  third  abdominal  segment  with  seven  annulets, 
annulets  1,  3,  and  5  setiferous  and  3  and  5  with  transverse  row  of  glandu- 
bae; abdominal  segments  2-8  and  10  with  larvapods;  antennae  with  five 
segments,  slender,  cylindro-conical;  body  uniformly  greenish,  with  dark 


37v>j  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  61 

dorsal  band  or  with  complicated  color-patterns;  tenth  abdominal  tergum 
convex,  suranal  or  caudal  protuberances  wanting;  ninth  abdominal  tergum 
with  six  annulets,  annulet  6  as  long  as  annulet  2;  thoracic  legs  normal, 
well  developed,  femur  with  ventro-distal,  conical  membranous  projection; 
clypeus  with  two  setae  on  each  side;  labrum  with  3-5  setae  on  each  side, 
with  or  without  a  median  longitudinal  depression;  maxillary  palpi  slender, 
normal;  galea  digit-like,  large;  lacinia  flattened,  with  a  row  of  10-15  setae 
on  the  oblique,  truncate  cephalic  margin;  stipes  with  a  sharp  triangular 
cephalo-ventral  projection;  labial  palpi  long,  slender,  with  segment  2 
longer  than  segment  1;  mandible  with  1,  2,  or  3-4  setae;  head  variously 
marked,  distinctly  and  densely  setiferous;  spiracles  on  third  annulet,  not 
winged;  larvapods  glabrous;  glandubae  distinct,  slender,  elongate  cylindro- 
conical,  sometimes  longer  than  adjacent  setae;  cuticle  microscopically  and 
densely  spinulate;  ventral  glands  wanting;  larvae  free  leaf-feeders. 

The  Tenthredininae  constitutes,  according  to  MacGillivray,  the  second 
subfamily  of  the  series  of  specialized  Tenthredinidae.  Rohwer  (1911) 
would  divide  the  subfamily  into  two  tribes,  Perineurini  and  Tenthredinini, 
using  the  position  of  the  propodeal  spiracles  and  shape  of  the  cephalic 
margin  of  the  scutellum  as  characters  for  differentiating  them.  In  many 
cases  the  larvae  resemble  those  of  the  Emphytinae. 

GENERA  OF  TENTHREDININAE 

1(4)      Mandibles  with  more  than  one  seta;  labrum  with  median  longitudinal  depression; 

legs  with  dorsal  aspect  of  femur  usually  less  than  twice  as  long  as  trochanter,  but 

often  subequal  to  it .2. 

2(3)      Mandibles  with  two  setae Macrophya  Dahlbom. 

3(2)      Mandibles  with  four,  occasionally  three,  setae Tenthredo  Linnaeus. 

4(1)      Mandibles  with  a  single  seta;  labrum  without  median  longitudinal  depression; 

legs  with  dorsal  aspect  of  femur  usually  twice  as  long  as  trochanter 5. 

5(6)      Body  with  complexly  patterned  markings  on  the  dorsum;  distal  segment  of  maxillary 

palpi  usually  longer  than  that  of  labial  palpi;  head  nearly  black . .  Tenthredo psis  Costa. 
6(5)      Body  without  complexly  patterned-markings  on  the  dorsum;  distal  segment  of 

maxillary  palpi  usually  not  longer  than  that  of  labial  palpi;  head  pale  or  light  brown 

Neopus  MacGillivray 

Tenthredo  psis  semilutea  Norton. — Body  on  dorsum  with  complexly 
patterned  purplish-black  markings  extending  to  supraspiracular  lines; 
two  lighter  colored  spots  on  dorso-meson,  their  apices  directed  cephalad, 
cephalic  one  much  larger  than  caudal;  large  spot  with  caudal  emargination 
on  latus  and  contiguous  to  mesal  triangles;  subspiracular  lobe  with  faint, 
minute  spots;  otherwise  ventral  half  of  body  including  legs  and  larvapods 
•whitish;  head  purplish  black  excepting  the  following  parts,  which  are 
white:  genae  including  antennae  and  antennariae,  lower  fourth  of  front, 
vertex  narrowly,  laterad  of  vertical  portion  of  epicranial  arms,  clypeus, 
labrum,  and  mouth-parts    except  tips  of  mandibles,  which  are  black; 


62  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [380 

fronto-clypeal  suture  sometimes  black;  in  young  specimens,  head  grayish 
and  body  entirely  whitish-green;  in  life  head  and  body  coated  with  a  waxy 
bloom;  annulation,  (3,  5,  1),  (2,  4),  6,  7; antennae,  5,  2,  (1,  3,  4);  maxillary 
palpi,  (4,  2),  3,  1;  labial  palpi  with  distal  segment  twice  as  long  as  the  pre- 
ceding segment,  but  subequal  in  length  to  or  shorter  than  distal  segment 
of  maxillary  palpi;  labrum  usually  with  three  setae  on  each  side  and 
without  median  longitudinal  depression;  mandible  with  one  seta;  legs 
with  trochanter  one-half  as  long  as  tibia,  femur  slightly  longer  than 
tibia;  glandubae  half  as  long  as  adjacent  setae;  length,  18  mm.;  width  of 
head,  1.8  mm.;  on  Thalictrum  polygonum;  Y-8,-92-1-1. 

Neopus  14-punctatus  Norton. — Head  pale  creamy-white  with  brown 
spots  on  dorso-meson  of  vertex,  caudad  of  ocellarae,  and  on  front,  frontal 
spots  much  darker;  body  whitish  green,  dorsum  with  a  grayish  shade,  bor- 
dered along  supraspiracular  lines  with  narrow  grayish  bands,  dorso-meson, 
especially  on  thorax,  with  fine  double  bands;  venter  including  legs  and 
larvapods  whitish;  annulation,  (1,  5,  3),  (2,  4,  6,  7);  antennae,  (5,  1),  2, 
(3,  1);  maxillary  palpi,  4,  2,  (3,  1);  labial  palpi  with  distal  segment  one- 
fourth  longer  than  preceding  segment,  but  subequal  to  distal  segment  of 
maxillary  palpi;  labrum  with  three  setae  on  each  side,  median  longitudinal 
depression  wanting;  mandible  with  single  seta;  legs  with  trochanter  nearly 
one-half  as  long  as  femur,  tibia  equal  in  length  to  femur;  glandubae  more 
than  half  the  length  of  adjacent  setae;  length  of  body,  18  mm.;  width  of 
head,  1.8  mm.;  on  Podophyllum  pdtatum:  Y-205-1-1. 

Tenthredo  bilineata  MacGillivray. — Head  whitish  green  with  vertex 
brown  dorsad  of  genae  except  narrow  line  along  epicranial  stem,  vertical 
furrows,  and  caudad  and  dorsad  of  ocularia;  body  on  dorsum  with  series  of 
triangular  brownish  markings;  triangle  with  apex  directed  cephalad  and 
with  minute  deep  brown  spot  at  each  basal  angle,  the  triangle  divided  on 
meson  by  a  faint  light  line;  supraspiracular  line  with  light  brownish  in- 
definite band;  venter  including  legs  and  larvapods  whitish;  annulation, 
(3,  1,  5),  (7,  6,  2,  4);  antennae,  5,  (1,  2,  3,  4);  maxillary  palpi,  (4,  2),  1,  3; 
labial  palpi  with  distal  segment  nearly  twice  as  long  as  the  preceding  seg- 
ment and  shorter  than  distal  segment  of  maxillary  palpi;  labrum  with  five 
setae  on  each  side  and  with  median  longitudinal  depression;  mandibles  with 
four  setae;  legs  with  trochanter  nearly  as  long  as  femur,  tibia  longer  than 
femur;  glandubae  conical,  large,  subequal  in  length  to  adjacent  setae; 
length  of  body,  21  mm.;  width  of  head,  2  mm.;  on  Geranium  maculatum: 
Y-175-2. 

Macrophya  Dahlbom 

Body  usually  whitish  green,  on  dorsum  with  or  without  grayish  band, 
latus  sometimes  with  small  black  spots;  head  usually  marked  on  vertex; 
antennae  with  segment  1  or  2  longest  or  all  segments  subequal  in  length; 


381]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  63 

maxillary  palpi  usually  with  segments  2  and  4  subequal  in  length;  mandible 
with  two  setae;  labrum  with  three  setae  on  each  side,  with  median  longitu- 
dinal depression;  trochanter  distinctly  shorter  than  femur;  head  and 
body  in  life  usually  coated  with  a  thin  whitish  waxy  bloom;  dorsal  vessel 
usually  showing  thru  cuticle  as  a  dark  fine  line;  setae  microscopic;  gland u- 
bae  shorter  or  longer  than  adjacent  setae;  length,  16-21  mm. 

SPECIES  OF  MACROPHYA 

1(4)  Head  pale  brown,  with  or  without  a  minute  brown  spot  at  the  caudal  end  of  epi- 
cranial stem;  body  on  dorsum  with  light  or  pale  grayish  band,  darker  along  supra- 
spiracular  lines,  band  sometimes  obsolete;  venter  whitish,  including  legs  and 
larvapods;  tenth  abdominal  segments  unmarked;  labial  palpi  with  distal  segment 
twice  as  long  as  the  preceding  segment;  glandubae  very  small,  shorter  than  adjacent 
setae;  setae  microscopic;  head  and  body  coated  with  thin  waxy  bloom;  on  Primus 
serotina;  subgregarious 2. 

2(3)      Larger  species,  length,  20  mm.;  width  of  head,  1.8  mm. ;  annulation,  (1, 5),  3,  (4, 6,  7), 

2;  antennae,  (2, 1),  (3, 4, 5);  maxillary  palpi,  2,  (1, 3, 4);  Y-126.-126-3-C-1 

flicta  MacGillivray. 

3(2)      Smaller  species,  length,  16  mm.;  width  of  head,  1.8  mm.;  annulation,  (5,  1,  3),  4,  6, 

2,  7;  antennae,  2,  (5,  1, 4),  3;  maxillary  palpi,  (2, 4),  (3, 1);  Y-59-3-1,-59-4-1 

fistula  MacGillivray. 

4(1)  Head  with  a  large  blackish  spot  on  dorsal  part  of  vertex,  often  with  black  spots 
caudad  of  ocellarae;  body  with  or  without  distinct  grayish  dorsal  band,  on  latus  with 
rows  of  black  or  yellowish  spots;  venter  usually  whitish;  pedal  line  sometimes  with 
fine  gray  markings 5. 

5(8)  Body  entirely  whitish;  head  on  vertex  usually  with  a  dorsal  spot  not  expanding 
distad;  without  spots  caudad  of  ocellarae 6. 

6(7)  Body  with  a  row  of  small  black  spots  along  supraspiracular  lines,  two  spots  to  each 
segment,  cephalic  spot  larger  than  caudal;  tenth  abdominal  tergum  unmarked; 
annulation,  (1,  3,  5)  (4,  7),  (6,  2);  antennae,  (4,  1),  2,  3;  legs  with  femur  more  than 
twice  as  long  as  trochanter,  tibia  shorter  than  femur,  coxa  with  grayish  marking; 
glandubae  longer  than  adjacent  setae;  length  of  body,  22  mm.;  width  of  head,  2.3 
mm.;  on  Sambucus;  Y-8.11,-11 tibiator  Norton. 

7(6)  Body  without  a  row  of  small  black  spots  along  supraspiracular  lines,  but  with 
yellowish  spots  on  latus  instead,  which  are  obsolete  in  alcoholic  specimens;  annula- 
tion, (3,  5,  1),  (2,  7,  4,  6);  antennae.  1,  (2,  3,  4,  5);  maxillary  palpi,  (4,  2),  (1,  3); 
labial  palpi  with  distal  segment  only  one-fourth  longer  than  the  preceding  segments; 
legs  with  trochanter  slightly  shorter  than  tibia,  femur  slightly  longer  than  tibia; 
length  of  body,  22  m.;  width  of  head,  2.2  mm.;  on  Sambucus  racemosa;  Y-8.11 
-2(?)-3 e.pinota  Say. 

8(5)  Body  not  entirely  whitish,  dorsum  with  dark  dorsal  band;  latus  with  one  or  more 
rows  of  distinct  black  spots;  head  on  vertex  with  a  dorsal  spot  expanding  distad, 
broadly  T-shaped,  caudad  of  ocellarae  with  spots;  tenth  abdominal  segment  with  a 
minute  black  spot  on  caudo-meson;  venter  lighter  in  color 9. 

9(10)  Body  on  latus  with  grayish  band  darker  in  color  than  dorsal  band  and  with  only 
one  row  of  distinct  black  spots;  supraspiracular  lines  with  a  row  of  distinct  spots; 
dorso-lateral  lines  with  a  row  of  smaller,  inconspicuous  spots;  subspiracular  line 
with  very  faint  grayish  spots,  nearly  obsolete ;  pedal  lines  with  grayish  linear  markings ; 
annulation,  1,  (3,  5),  (7,  2,  4),  6;  antennae,  (1,  2,  3,  4,  5);  maxillary  palpi,  (2.  4), 
1,3;  labial  palpi  with  distal  segment  not  quite  twice  as  long  as  the  preceding  segment; 


64  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [382 

legs  with  femur  twice  as  long  as  trochanter  and  slightly  longer  than  tibia;  length  of 

body,  19  mm.;  width  of  head,  2  mm.;  on  Aster  prenanthoides ;  Y-8,  81(?) 

lineata  Norton. 
10(9)  Body  on  latus  with  grayish  band  lighter  in  color  than  grayish-purple  dorsal  band  and 
with  three  rows  of  distinct  black  spots;  dorso-lateral  and  supraspiracular  lines  with 
rows  of  small  spots,  two  spots  to  each  segment,  with  caudal  spot  much  smaller  and 
sometimes  nearly  obsolete;  spots  on  supraspiracular  line  largest;  pedal  line  with  a 
row  of  spots,  two  to  each  segment,  with  cephalic  spots  smaller  than  caudal;  head 
with  black  spots  on  vertex  large,  sometimes  coalesced,  covering  entire  vertex  except 
genae  and  vertical  furrows;  front  with  faint  gray  spot;  annulation,  (3,5, 1),  (7,2,4,6); 
antennae,  2,  (1,  5),  (3,  4);  maxillary  palpi,  (4,  2),  (1,  3);  labial  palpi  with  distal 
segment  not  quite  twice  as  long  as  the  preceding  segment;  legs  with  trochanter  more 
than  one-half  as  long  as  tibia,  femur  equal  in  length  to  tibia;  length  of  body,  21.5 
mm.;  width  of  head,  2.1  mm.;  on  Solidago  juncea  and  Rudbeckia  laciniata;  Y-160-2, 
-160-1 pulchdla  Klug. 

Subfamily  Cimbicinae 

Body  cylindrical  (Fig.  14),  tapering  uniformly  caudad,  apparently 
glabrous,  prothorax  narrowed;  segmentation  indistinct;  annulation  fine,  7, 
(2,  3,  4),  (1,  5,  6),  annulets  2,  4,  and  7  microscopically  setiferous;  thoracic 
legs  normal  in  form,  with  five  segments,  femur  slightly  longer  than  tibia; 
larvapods  on  abdominal  segments  2-8  and  10,  divided  into  two  unequal 
lobes  on  the  distal  surface,  few  setae  on  the  dorso-caudal  aspect,  and  none 
on  the  cephalic  aspect  as  viewed  from  side;  tenth  abdominal  tergum  with- 
out suranal  protuberances;  suranal  and  subanal  lobes  with  several  short 
setae;  head  large,  rather  thickly  setiferous,  normal  in  form;  labrum  sub- 
divided by  diverging  depression  into  median  lobe  and  two  lateral  lobes, 
sometimes  asymmetrical;  antennae  with  a  single  segment,  button-like  but 
chitinized;  ventral  glands  wanting;  glandubae  microscopic  or  minute  and 
stalked,  sometimes  distinct  conical  tubercles;  spiracles  distinctly  winged; 
conspicuous  spiracular  glands  located  dorsad  of  each  spiracle  of  abdominal 
segments  2-8;  cuticle  microscopically  and  densely  spinulate  or  verrucose; 
mouth-parts  normal  in  form,  maxillary  and  labial  palpi  rather  slender, 
galea  very  thick,  curved  mesad  at  distal  end,  sericos  large,  distinctly 
chitinized,  pear-shaped,  U-shaped,  or  V-shaped;  stipes  with  a  distinct 
triangular  projection  on  the  dorsal  or  cephalic  margin;  body  covered 
with  waxy  bloom  in  life;  larvae  ejecting  yellowish  fluid  from  spiracular 
glands  when  disturbed;  free  leaf -feeders,  sometimes  semigregarious. 

The  Cimbicinae  is  a  small  compact  subfamily  consisting  of  few  genera 
and  a  limited  number  of  species  in  the  Nearctic  region.  Systematists  are 
in  accord  in  the  general  conception  of  the  group,  but  Konow  includes  the 
Perginae  in  his  subfamily  Cimbicini.  Cimbex  americana,  with  its  several 
varieties,  is  a  well-known  representative  of  this  subfamily. 


383]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  65 

GENERA  OF  CIMBICINAE 

1(4)  Body  in  general  whitish,  without  minute  colored  spots 2. 

2(3)  Dorsum  of  body  with  a  black  median  stripe Cimbex  Olivier. 

3(2)  Dorsum  of  body  without  a  black  median  stripe Trichiosoma  Leach. 

4(1)  Body  in  general  not  whitish,  but  with  minute  colored  spots Abia  Leach. 

Cimbex  Olivier 

Larvae  very  large,  distinctly  robust,  largest  of  all  saw-fly  larvae,  40-50 
mm.  in  length;  body  whitish  with  a  distinct  dorso-mesal  black  line;  labrum 
distinctly  asymmetrical,  dextral  portion  larger  than  sinistral,  median 
cephalic  or  ventral  emargination  distinct  and  deep;  body  with  distinct 
minute  warts  or  conical  glandubae,  cuticle  microscopically  verrucose; 
spiracular  glands  semicircular;  sericos  of  labium  pear-shaped  with  its  nar- 
row neck  directed  dorsad  or  cephalad;  lateral  lobes  small  but  prominent  with 
several  conical  tubercles;  maxillary  palpi,  2,  4,  3,  1;  labial  palpi,  1,  2; 
antennae  mound-like,  wider  than  high 

Cimbex  americana  Leach. — Length,  50  mm.;  head,  5  mm.  wide;  head 
white,  creamy,  microscopically  brownish  verrucose;  black  median  stripe  on 
dorsum  extending  from  prothorax  to  the  middle  of  eighth  abdominal 
segment;  conical  tubercles  or  glandubae  on  sublateral  lobes  larger  than 
elsewhere  and  4-7  in  number;  larvae  solitary;  on  willow,  elm,  poplar, 
maple,  alder,  linden,  etc.;  Y-68,  -8,  -182,  M-99. 

Trichiosoma  Leach 

Larvae  very  large,  somewhat  slender,  entirely  white;  labrum  slightly 
asymmetrical,  right  side  larger  than  sinistral,  median  ventral  emargina- 
tion deep,  but  not  reaching  the  median  lobe;  body  not  warty;  glandu- 
bae microscopic,  stalked,  arising  from  very  low  swellings;  cuticle  micro- 
scopically verrucose;  spiracular  glands  semicircular;  sericos  of  labium 
U-shaped,  narrower  on  dorsal  or  cephalic  end;  lateral  lobes  not  prominent, 
without  conical  tubercles;  maxillary  palpi  2,  4,  3,  1;  labial  palpi,  1,  2; 
antennae  conical,  longer  than  wide. 

Trichiosoma  sp. — Length,  38  mm. ;  width  of  head,  4  mm. ;  head  creamy 
white,  body  whitish;  solitary;  on  willow,  poplar,  alder,  wild  cherry; 
M-78,  -44. 

Abia  Leach 

Larvae  large,  rather  plump,  greenish  or  grayish  green  with  minute 
yellowish  or  blackish  spots;  labrum  symmetrical,  median  ventral  emargi- 
nation only  slightly  indicated,  broad;  body  without  warts  or  tubercles; 
cuticle  microscopically  and  densely  spinulate;  glandubae  stalked  and 
minute,  not  arising  from  swellings;  spiracular  glands  semicircular;  sericos 
of  labium  V-shaped,  widest  at  dorsal  or  cephalic  end;  sublateral  lobes 


66  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [384 

inconspicuous,  with  several  glandubae;  maxillary  palpi,  (4,  2)  3,  1;  labial 
palpi  with  segments  subequal;  antennae  conical,  usually  as  wide  as  long. 

SPECIES  OF  ABIA 

1(2)  Body  with  a  broad  dorso-mesal  yellowish  stripe  between  subdorsal  lines;  dorsum 
above  supraspiracular  lines  shaded  brownish  gray;  head  brownish  gray  except 
front,  genae,  clypeus,  and  labrum  which  are  lighter;  ocellarae  white;  body  dorsad  of 
supraspiracular  lines  shaded  grayish  or  brownish,  venter  pale  whitish-green;  dorsum 
between  subdorsal  lines  yellowish  white;  body  with  four  rows  of  minute  black 
spots;  middorsal  row  with  a  large  spot  on  annulet  7  and  a  smaller  spot  on  annulets  2 
and  4;  subdorsal  row  with  a  large  spot  on  annulet  7,  with  a  bright  yellow  spot  between 
two  black  spots  mentioned  above;  supraspiracular  row  with  a  spot  on  annulets  2 
and  4  and  a  very  small  spot  on  annulet  7;  subspiracular  row  with  a  spot  at  the 
ventral  ends  of  annulets  3  and  4;  a  yellow  spot  caudad  of  each  spiracle;  length, 

26  mm.;  width  of  head,  2.7  mm.;  on  honeysuckle;  semigregarious;  Y-8.13 

amerkana  Cresson. 

2(1)  Body  with  a  broad  dorso-mesal  yellowish  stripe  between  subdorsal  lines;  dorsum 
above  supraspiracular  lines  not  shaded  brownish-gray,  but  body  generally  greenish . .  3. 

3(4)  Pedal  line  without  distinct  more  or  less  continuous  smoky  brownish  gray  band; 
black  spots  directly  ventrad  of  spiracles  never  present;  second  annulet  without  minute 
but  distinct  spots  dorsad  of  lateral  large  spots;  head  grayish  brown  except  front, 
genae,  and  clypeus,  labrum  lighter;  ocellarae  white;  body  entirely  grayish  green, 
dorsum  between  subdorsal  lines  concolorous  with  other  parts,  the  dorso-meson 
with  a  narrow  yellowish  line;  five  rows  of  minute  black  spots:  meso-dorsal  row  with 
a  larger  spot  on  annulet  7  and  a  smaller  spot  on  annulets  2  and  4;  subdorsal  row  with  a 
larger  spot  on  annulet  7  and  very  minute  and  often  obscure  spot  on  annulet  2,  and 
larger,  distinct,  often  subdivided,  spot  on  annulet  4,  the  latter  two  nearer  to  meson 
than  the  regular  subdorsal  spots;  lateral  row  with  a  large  spot  between  annulets 
2  and  3;  supraspiracular  row  with  a  smaller  spot  on  annulets  4  and  7;  subspiracular 
with  a  larger  spot  at  the  ventral  end  of  annulets  3  and  4;  a  bright  yellow  spot  between 
mesal  and  subdorsal  black  spots  on  annulet  7;  length,  28  mm.;  width  of  head,  2.8 
mm.;  on  Triosteum  aurantiacum;  Y-8.13-2,  M-196 injlata  Norton. 

4(3)  Pedal  line  with  distinct,  more  or  less  continuous  smoky  brownish  gray  band ;  black 
spots  directly  ventrad  of  spiracles  always  present,  at  least  on  majority  of  segments; 
one  or  two  minute  black  spots  on  second  annulet  dorsad  of  large  lateral  spots  always 
present;  length,  30  mm.;  width  of  head,  2.9  mm.;  on  honeysuckle;  Y-104,  G-583, 
both  from  Urbana,  HI. ;  larvae  resemble  A .  injlata  in  markings  and  general  appearance 
but  differ  as  above Abia  sp.  1. 

Subfamily  Hoplocampinae 

Larvae  (Fig.  15)  small;  body  cylindrical,  slender;  segmentation  and 
annulation  sometimes  obsolete;  third  abdominal  segment  with  four  or  five 
annulets,  annulets  2  and  3  or  2  and  4  setiferous  or  all  annulets  glabrous; 
larvapods  present  on  abdominal  segments  2-7  and  10,  glabrous  or  setiferous, 
sometimes  very  rudimentary;  ventral  glands  usually  present  on  the  meson 
of  abdominal  segments  1-7;  body  greenish  or  yellowish,  striped  or  spotted 
or  without  any  markings;  tenth  abdominal  tergum  with  or  without  suranal 
protuberances,  if  present,  often  more  than   two  in  number;  antennae 


385J  LARVAE  OF  THE  TENTHREDIN01DEA—YUASA  67 

conical,  with  five  segments,  or  flattened,  with  four,  sometimes  apparently 
with  three;  larvae  free  leaf-feeders  and  borers  in  fruits  or  petioles  of  leaves. 

The  Hoplocampinae  as  defined  by  MacGillivray  contains  at  present 
five  genera,  Marlattia,  Hoplocampa,  MacGillivrayella,  Hemichroa,  and 
Craterocercus,  and  represents,  together  with  Dineurinae,  a  series  in  which 
the  anal  veins  have  been  modified  before  the  loss  of  the  radial  cross-vein. 
Formerly  Rohwer  (1910,  1911a,  1913b)  considered  Hoplocampa  and 
MacGillivrayella  as  constituting  a  subfamily  Hoplocampinae  but  later 
(1918c)  he  abandoned  this  idea  and  united  these  genera  with  six  other 
genera  and  subgenera  to  form  the  tribe  Hemichroini  of  his  subfamily 
Nematinae,  as  others  have  done.  With  the  exception  of  two  genera, 
Platycampus  and  Anoplonyx,  Rohwer's  tribe  Hemichroini  becomes 
coextensive  with  our  Hoplocampinae.  Cameron  (1883)  considered  this 
subfamily  as  forming  "a  connecting  link  between  the  Selandrides  and 
Nematides."  There  are  reasons  for  indicating  a  close  relation  between 
this  subfamily  and  Nematinae.  A  study  of  the  larvae  confirms  the  con- 
tention of  Rohwer  (1918c)  that  the  grouping  of  Caliroa  and  Phyllotoma  with 
the  Hoplocampinae,  as  was  done  by  Konow  and  Enslin,  is  untenable. 

It  must  be  stated  here  that  since  only  three  genera,  each  represented 
by  a  single  species,  were  available  for  this  study,  the  preceding  definition 
of  the  subfamily  is  necessarily  incomplete. 

GENERA  OF  HOPLOCAMPINAE 

1  (2)      Tenth  abdominal  tergum  without  caudal  protuberances Marlattia  Ashmead . 

2(1)      Tenth  abdominal  tergum  with  caudal  protuberances 3. 

3(4)      Caudal  protuberances  more  than  two  in  number;  larvapods  well  developed;  third 

abdominal  segment  with  five  annulets;  free  leaf -feeders Hemichroa  Stephens. 

4(3)      Caudal  protuberances  two  in  number  on  caudal  projection;  larvapods  rudimentary; 

third  abdominal  segment  with  four  annulets;  leaf-petiole  borer.  Caulocampus  Rohwer. 

Hemichroa  Stephens 

Larvae  small,  greenish;  length  less  than  18  mm.;  body  slender,  tapering 
uniformly  caudad;  third  abdominal  segment  with  five  annulets  2  and  4 
setiferous;  tenth  abdominal  tergum  with  several  conical  caudal  protuber- 
ances on  its  caudal  margin;  antennae  distinctly  conical,  with  five  segments, 
as  long  as  the  longest  diameter  of  antennaria;  antennal  segment  1  cres- 
centic,  dorsal  in  position,  extending  nearly  the  entire  length  of  antennaria, 
segment  2  complete  or  incomplete,  reduced  to  mere  line  on  cephalic 
aspect,  segments  3  and  4  ring-like  tho  reduced  in  length  on  cephalic  portion, 
segment  5  conical  or  peg-like,  bluntly  pointed  at  apex;  thoracic  legs 
with  tibia  subequal  in  length  to  femur;  larvapods  glabrous;  spiracles  faintly 
winged;  glandubae  distinct  and  large;  larvae  free  leaf -feeders. 

Hemichroa  dyari  Rohwer. — Larvae  yellowish  green;  length,  16  mm.; 
head  blackish;  body  with  blackish  dorso-lateral  lines  and  interrupted 


68  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [386 

blackish  lines  on  subspiracular  and  pedal  lines;  tenth  abdominal  tergum 
with  six  to  seven  conical  protuberances,  suffused  with  brown;  surpedal  and 
subspiracular  lobes  with  two  setae  and  two  glandubae;  glandubae  with 
diameter  twice  that  of  anal  setae;  annulation,  (1,  2,  4)  3,  5;  on  alder;  Y-39- 
-1-1,-8.73  (?)  -l,-8.73(?)-2,  C-8. 

Marlattia  Ashmead 

Larvae  comparatively  very  small,  greenish,  with  or  without  stripes 
or  spots;  body  cylindrical,  tapering  caudad;  third  abdominal  segment 
with  five  annulets,  annulets  apparently  glabrous;  tenth  abdominal  seg- 
ment without  caudal  protuberances;  antennae  with  four  segments,  flat- 
tened; segment  1  small,  incomplete;  segments  2  and  3  complete  but 
reduced  to  narrow  line  on  cephalic  aspect;  segment  4  minute,  mamma- 
like; head  sparsely  setiferous,  setae  increasing  in  length  on  the  lower 
portion;  thoracic  legs  normal  in  form,  tibia  subequal  in  length  to  femur;  lar- 
vapods  with  a  few  setae;  spiracles  minute,  un winged;  glandubae  micro- 
scopic. 

Marlattia  laricis  Marlatt. — Head  pale  yellowish,  body  greenish  with 
faint  subdorsal  lines;  third  abdominal  segment  with  five  annulets,  (1,  2) 
4,  3,  5;  larvapods  with  three  setae;  suranal  lobe  with  a  few  setae  on  caudo- 
ventral  aspect;  small  larvae,  length,  10  mm.;  M-57. 

Caulocampus  Rohwer 

Larvae  very  small;  length  less  than  10  mm. ;  body  subcylindrical,  taper- 
ing at  prothorax,  constricted  suddenly  on  the  ultimate  segment,  not 
spotted  or  striped,  but  whitish,  sparsely  and  microscopically  setiferous; 
third  abdominal  segment  with  four  annulets,  annulets  2  and  3  with  very 
minute  setae;  thoracic  legs  minute,  with  five  segments,  tibia  longer  than 
femur;  abdominal  segments  2-7  with  rudimentary  larvapods  represented  by 
spinulate  swellings;  tenth  abdominal  tergum  much  smaller  in  diameter 
than  preceding  segments,  strongly  converging  caudad,  caudal  margin 
produced  and  chitinized,  a  pair  of  minute  brownish  caudal  protuberances 
on  the  caudal  margin  of  the  projection;  head  small,  sparsely  and  minutely 
setiferous;  ocellarae  represented  by  pigmented  spots,  distinct,  ring-like, 
ocularia  wanting;  antennae  apparently  with  three  segments,  conical,  seg- 
ments 1  and  2  incomplete,  segment  3  slender,  peg-like;  mouth-parts 
normal  and  conspicuous  tho  small;  spiracles  not  winged;  glandubae 
obsolete;  in  young  specimens  dorsum  of  abdominal  segments  1-7,  with  a 
pair  of  protuberances  on  annulet  2;  larvae  borers  in  leaf -petiole. 

This  genus  is  monotypic  and  unique  in  the  reduction  of  larvapods 
and  ocellarae  and  in  the  possession  of  modified  caudal  projection  on  the 
ultimate  segment  with  rudimentary  caudal  protuberances.     In  this  last 


387]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  69 

character  the  larvae  of  this  genus  resemble  those  of  certain  species  of 
Pontania.  The  modifications  of  the  body  are  undoubtedly  correlated  with 
the  boring  habit  of  the  larvae.  MacGillivray  still  considers  this  genus 
as  without  question  belonging  to  the  Cladiinae,  but  Rohwer  regards  it  as 
belonging  to  his  tribe  Hemichroini.  It  is  dealt  with  here  under  the  Hop- 
locampinae  because  the  larvae  more  closely  resemble  larvae  of  this  sub- 
family than  they  do  those  of  the  Cladiinae. 

Caulocampus  acericaulis  MacGillivray. — Length,  8  mm.;  width  of  head, 
.8  mm.;  head  light  brown,  body  straw-yellow;  resembles  larvae  of  weevils 
in  general  appearance;  mouth-parts  normal  in  form;  in  young  specimens 
head  yellowish  and  body  whitish;  annulation,  2,  1,  3,  4;  maxillary  palpi, 
3,  2,  1,  4,  segments  brown,  slender;  galea  digit-like,  very  small;  thoracic 
legs  with  very  small  tibiae,  tibia  subequal  in  length  to  maxillary  palpus; 
tenth  abdominal  tergum  with  many  minute  setae  evenly  and  promiscu- 
ously scattered,  not  concentrated  on  subanal  lobe;  larvae  bore  into  the 
petioles  of  maple-leaves;  Y  (generosity  of  Dr.  W.  E.  Britton,  New  Haven, 
Conn.). 

Subfamily  Dineurinae 

Larvae  small;  body  subcylindrical,  flattened  on  venter  or  cylindrical, 
usually  tapering  toward  the  caudal  end,  greenish  or  yellowish,  often  with 
dorsum  darker,  never  with  bright-colored  markings;  glabrous  or  setiferous; 
head  small,  light  greenish  or  yellowish,  never  with  distinct  markings; 
ocellarae  blackish;  mouth-parts  usually  brownish;  thorax  wider  than  the 
remainder  of  body,  thoracic  legs  well-developed,  caudal  pairs  larger  than 
the  cephalic,  directed  laterad;  segmentation  distinct;  annulation  indistinct; 
larvapods  on  abdominal  segments  2-7  and  10,  sometimes  rudimentary; 
intersegmental  coria  often  distinct  and  whitish;  larvae  feed  on  under  side 
or  upper  side  of  leaves,  eating  the  parenchymatous  layers  only  or  feeding 
on  edges  of  leaves  or  mining  in  the  leaves;  ultimate  stage  glabrous  and 
yellowish;  pupation  in  single-layered  parchment-like  cocoons  in  the 
ground;  some  species  with  nauseating  odor. 

The  Dineurinae  as  limited  by  MacGillivray  contains  three  genera, 
Dineura,  Mesoneura,  and  Pseudodineura,  and  includes  not  over  twenty- 
five  species,  which  are  mostly  distributed  in  Europe  and  North  America. 
This  subfamily  resembles  in  wing-type  the  Hoplocampinae.  Systematists 
do  not  agree  in  the  exact  position  of  the  small  European  genus  Pseudo- 
dineura. Konow  would  place  Dineura  in  his  tribe  Nematides  but  both 
Mesoneura  and  Pseudodineura  in  his  tribe  Blennocampides.  Rohwer, 
on  the  other  hand,  would  associate  Dineura  and  Mesoneura  in  his  tribe 
Nematini,  and  is  not  quite  certain  whether  Pseudodineura  also  belongs 
to  this  tribe  or  not.  Cameron,  who  described  the  larva  of  Pseudodineura 
parvulus  under  the  name  of  Dineura  despecta,  altho  aware  of  the  differences 


70  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [388 

between  this  species  and  its  allies  and  other  species  of  Dineura,  hesitated 
to  agree  with  Thompson  in  associating  it  with  Blennocampa.  The  vena- 
tion certainly  indicates  close  relationship  between  Dineura  and  Pseudo- 
dineura.  The  latter  is  characterized  in  its  larval  stages  by  the  leaf-mining 
habit  and  structural  modifications  due  to  this  mode  of  life,  altho  appar- 
ently these  do  not  constitute  very  striking  distinctions  if  one  may  judge  from 
published  records.  Since  previous  authors  failed  to  study  the  structures 
of  the  head  more  carefully,  and  since  these  are  of  great  taxonomic  im- 
portance, and  also  on  account  of  the  discrepancy  between  the  larval 
habits  of  the  three  genera  in  question,  it  is  impossible  to  pass  judgment  on 
their  affinity  until  more  is  known  with  regard  to  their  larval  structures 
and  habits,  particularly  in  the  case  of  Pseudondineura. 

The  life  history  of  the  subfamily  has  been  recorded  by  Girard,  Cameron, 
and  Brischke  and  Zaddach.  The  larvae  of  the  American  species  are  un- 
known, and  as  none  of  the  European  species  have  been  available  for  study 
the  definition  of  the  Dineurinae  here  given  is  tentative,  and  is  based  on 
descriptions  and  figures  published  by  Cameron  (1882)  and  by  Brischke 
and  Zaddach  (1883). 

Subfamily  Cladiinae 

Larvae  (Fig.  16)  of  small  to  medium  size;  body  rather  flattened,  wider 
than  high,  slightly  tapering  caudad,  conspicuously  hairy,  greenish  or  with 
segmentally  arranged  spots  on  dorsum  darkly  shaded;  segmentation  and 
annulation  usually  distinct;  third  abdominal  segment  with  four  annulets, 
annulets  1,  2,  and  3  setiferous,  setae,  especially  on  annulets  2  and  3, 
arising  from  wart-like  tubercles,  long,  often  curved,  always  microscopically 
barbed,  never  branched,  some  of  the  setae  distinctly  longer  than  others; 
annulet  4  narrow  and  glabrous;  larvapods  present  on  abdominal  segments 
2-7  and  10  well  developed,  long,  distal  portion  often  dilated,  appearing  as  if 
subdivided,  often  curved  mesad,  always  with  few  setae;  ventral  glands  small 
but  always  present  on  abdominal  segments  1-7;  tenth  abdominal  tergum 
without  caudal  protuberances  but  with  many  setae  of  varying  length; 
thoracic  legs  spreading  flat  laterad;  femur  with  a  ventro-distal  projection, 
subequal  in  length  to  tibia;  antennae  with  four  segments,  subconical,  large; 
segment  1  complete  or  incomplete,  segment  2  complete,  thicker,  dorsal  or 
caudo-dorsal  portion  with  clear  spaces,  segment  3  smaller  and  narrower 
than  segment  2,  segment  4  minute,  conical;  spiracles  never  winged;  glandu- 
bae  small  or  obsolete;  sericos  usually  very  wide,  occupying  nearly  four- 
fifths  of  the  width  of  the  totaglossa;  larvae  external  leaf-feeders. 

The  Cladiinae  is  a  small  subfamily  and  according  to  MacGillivray 
consists  of  six  genera;  Anoplonyx,  Platycampus,  Priophorus,  Cladius,  and 
Trichiocampus.  The  first  three  genera  are  placed  in  the  tribe  Hemichroini 
of  his  subfamily  Nematinae  by  Rohwer  (1911,  1918),  who  states  that 


389]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  71 

"the  characters  of  both  the  adult  and  the  larva  point  out  subfamily 
difference  between  Caulocampus  and  Priophorus"  and  that  the  former 
superficially  resembles  Hoplocampa  in  all  stages  but  is  really  related  to 
Craterocerus.  The  difference  of  opinion  is  due  to  the  different  value 
placed  by  these  two  writers  on  the  presence  or  absence  of  the  radial  cross- 
vein  in  differentiating  the  subfamilies.  The  genus  Caulocampus  has  been 
discussed  in  connection  with  the  Hoplocampinae  because  the  larvae  of  this 
genus  are  very  different  from  those  of  the  Cladiinae  both  morphologically 
and  biologically  and  because  they  are  more  naturally  associated  with  the 
larvae  of  the  Hoplocampinae.  Anoplonyx  is  represented  in  the  Neartic 
region  by  a  single  species.  Platycampus  includes  four  American  species, 
two  of  which  have  been  recognized  in  the  immature  stages.  P.  americana 
feeds  on  Populus  and  P.  juniperi  on  juniper.  None  of  these  larvae  have 
been  examined. 

GENERA  OF  CLADIINAE 

1(2)  Body  spotted,  with  a  row  of  blackish  or  brownish  spots  on  subdorsal,  supraspiracular 
or  subspiracular  lines;  setae  usually  recurved  exceedingly  long,  longest  ones  longer 
than  one-half  the  height  of  the  head;  annulet  1  usually  with  one  seta  on  each  side  of 
meson Trichiocampus  Hartig. 

2(1)  Body  never  spotted;  setae  usually  straight,  long,  but  the  longest  ones  never  distinctly 
longer  than  half  the  height  of  the  head;  annulet  1  always  with  more  than  one  seta  on 
each  side  of  meson,  usually  with  four  to  six  setae 3. 

3(4)  Head  with  spots,  usually  with  blackish  patches  on  dorso-meson  of  vertex  and  caudad 
of  each  ocellara;  body  dorsad  of  spiracular  lines  usually  shaded  darker  than  the 
venter;  body  sometimes  pinkish;  postsupraspiracular  tubercles  usually  with  three 
setae,  never  with  more  than  four Priophorus  Dahlbom. 

4(3)  Head  never  with  spots,  usually  uniformly  greenish;  body  dorsad  of  spiracular  lines 
never  shaded  darker  but  concolorous  with  venter;  body  never  pinkish  but  greenish 
yellow  or  whitish;  postsupraspiracular  tubercles  usually  with  six  setae,  never  with 
less  than  four Cladius  Rossi. 


Trichiocampus  Hartig 

Larvae  small  to  moderately  large,  length  from  10  to  25  mm.,  distinctly 
hairy,  with  segmentally  arranged  spots;  body  with  a  longitudinal  row  of 
blackish  or  brownish  spots  along  subdorsal,  supraspiracular,  or  subspiracu- 
lar lines;  annulet  4  shortest,  annulet  1  usually  with  one  and  sometimes  two 
setae  on  each  half  of  body,  annulet  2  with  tubercles  bearing  2-5  setae, 
annulet  3  with  three  warts,  two  dorsal  ones  bearing  4-5  setae  and  ventral 
one  with  6-9  setae,  postspiracular  tubercle  usually  with  two  setae,  sub- 
spiracular lobe  with  8-9  setae,  surpedal  lobe  with  6-10  setae;  setae  usually 
recurved,  variable  in  length,  longest  setae  nearly  subequal  in  length  to 
the  height  of  head;  warts  or  tubercles  with  setae  of  varying  length,  those 
on  annulet  1  among  the  shortest. 


72  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [390 

SPECIES  OF  TRICHIOCAMPUS 

1(2)  Body  with  three  pairs  of  longitudinal  rows  of  blackish  or  brownish  segmentally 
arranged  spots  along  subdorsal,  supraspiracular,  and  subspiracular  lines;  tenth 
abdominal  tergum  not  entirely  black  but  white  except  a  pair  of  minute  spots;  head 
light  brown  with  brownish  spots,  with  following  parts  dark  brown:  dorso-meson  of 
vertex,  dorsal  two-thirds  of  front,  and  vertex  dorso-caudad  of  each  ocellara  including 
gena;  preclypeus  whitish,  other  parts  pale,  including  occiput  between  vertical 
furrows;  a  row  of  brownish  spots  from  meso thoracic  to  ultimate  segment  along  each 
side  of  dorso-meson;  a  row  of  larger  spots  along  supraspiracular  line  from  pro  thoracic 
to  penultimate  segments;  another  row  of  much  smaller  spots  along  subspiracular 
lines  from  mesothoracic  to  eighth  abdominal  segment;  mesothoracic  and  metathoracic 
subspiracular  spots  more  than  twice  as  large  as  supraspiracular  spots  of  same  seg- 
ments; the  former  with  circular  white  areas  around  the  proximal  end  of  setae; 
prothoracic  supraspiracular  spots  small  and  indistinct;  third  abdominal  segment 
with  following  setal  map:  1,  3,  5,  1,  2,  5,  4,  8,  9-10,  8-9;  tenth  abdominal  tergum 
white,  except  a  pair  of  minute  spots;  subdorsal  spots  not  involving  tubercles  2  and  3; 
supraspiracular  spot  involving  tubercles  4  and  5;  subspiracular  spot  on  caudal  half  of 
subspiracular  tubercle;  maxillary  palpi  (2,  3),  1,  4;  head  in  younger  specimens  black- 
ish except  near  the  mouth;  body  without  spots;  in  older  specimens,  supraspiracular 
spots  appear  first,  then  subspiracular,  beginning  with  caudal  segments,  setae  on  tuber- 
cles sometimes  one  or  two  less  than  in  mature  specimens;  on  Populus;  length  of 
body,  12  mm.;  width  of  head,  1.5-1.6  mm.;  G-Onekama  and  Orono  on  oak,  length  of 
body,  13  mm.;  width  of  head,  1.7  mm.,  M-207.  (The  latter  resembles  the  former 
so  closely  and  indistinguishably,  altho  its  setae  may  be  slightly  fewer  in  number, 
that  they  are  considered  as  identical.) paetvius  MacGillivray. 

2(1)  Body  with  two  pairs  of  longitudinal  rows  of  blackish  or  brownish  segmentally 
arranged  spots  along  supraspiracular  and  subspiracular  lines;  tenth  abdominal 
tergum  entirely  black;  head  blackish,  with  paler  areas 3. 

3(4)  Mesothoracic  supraspiracular  spots  subequal  in  size  to  subspiracular  spots;  supra- 
spiracular spots  of  abdominal  segments  not  involving  postsupraspiracular  tubercles; 
prothoracic  supraspiracular  spots  minute  and  indistinct;  preclypeus,  labrum,  and 
genae  blackish;  metathoracic  subspiracular  spots  with  minute  but  distinct  circular 
whitish  areas  around  proximal  end  of  setae;  head  blackish,  paler  along  vertical 
furrows,  epicranial  arms,  and  postclypeus;  body  with  a  row  of  blackish  spots  from 
mesothoracic  to  penultimate  segment  along  supraspiracular  and  subspiracular  lines; 
tenth  abdominal  tergum  black;  third  abdominal  segment  with  the  following  setal 
map:  1,  3,  3,  0,  2,  4,  4,  5-6,  8-9,  6-8;  subspiracular  spot  involving  few  setae  directly 
ventrad  of  spiracles;  head  in  younger  specimens  entirely  blackish  and  spots  on 
subspiracular  lines  wanting;  maxillary  palpi,  (2,  3),  1,  4;  length  of  body,  18  mm.; 
width  of  head,  1.3  mm.;  on  Salix;  Y-151-1-1,-151-1-3;  M-100,-261.  (The  specimens 
in  the  Maine  collection  are  practically  identical  with  my  specimens  except  in  the 
number  of  setae  on  subspiracular  and  surpedal  lobes,  which  may  exceed  the  number 
given  byoneortwo) ^o&Atae MacGillivray. 

4(3)  Mesothoracic  supraspiracular  spots  not  subequal  to  but  distinctly  larger,  twice  or 
more,  than  subspiracular  spots;  supraspiracular  spots  of  abdominal  segments  in- 
volving postsupraspiracular  tubercles;  prothoracic  supraspiracular  spots  large  and 
distinct;  preclypeus,  labrum,  and  genae  not  blackish  but  pale  brown;  metathoracic 
subspiracular  spots  without  minute  but  distinct  whitish  circular  areas  around  the 
proximal  end  of  setae;  head  black,  paler  along  vertical  furrows,  epicranial  arms, 
clypeus,  labrum,  and  genae;  body  with  a  row  of  blackish  or  brownish  spots  from 
prothorax  to  penultimate  segment  along  supraspiracular  and  subspiracular  lines: 


391  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  73 

tenth  abdominal  tergum  black;  third  abdominal  segment  with  the  following  setal 
map:  2,  2,  3,  1,  2,  4,  4-5,  7-8,  8-9,  9-10;  mesothoracic  supraspiracular  spot  more  than 
twice  as  large  as  subspiracular  spot;  prothoracic  supraspiracular  spots  moderately 
large  and  distinct;  subspiracular  spot  involving  few  setae  in  caudal  portion  of  sub- 
spiracular tubercle;  mesothoracic  and  metathoracic  subspiracular  spots  without  circu- 
lar whitish  areas  around  the  proximal  end  of  setae;  maxillary  palpi  usually  3,  2, 1,  4; 
head  in  young  specimens  pale  brownish,  with  a  row  of  very  small  supraspiracular 
spots;  head  in  older  larvae  blackish,  body  spotted  like  mature  specimens  but  spots 
smaller;  on  Populus;  length  of  body,  21-23  mm.;  width  of  head,  2-2.1  mm.;  Y-172-1-1. 

Trichiocampus  sp.  1. 

Priophorus  Dahlbom 

Larvae  small,  hairy;  length  less  than  17  mm.;  body  with  dorsal  half, 
at  least  in  part,  usually  with  grayish  or  olivaceous  shade;  never  with 
spots;  annulet  1  with  a  transverse  row  of  several  setae;  annulet  2  with 
two  warts,  each  bearing  4-5  setae;  annulet  3  with  three  warts,  dorsal  two 
bearing  5-6  setae  each,  ventral  with  8-10  setae;  postsupraspiracular 
wart  usually  with  three  setae;  subspiracular  lobe  with  12-15  setae  and  sur- 
pedal  lobe  with  6-9;  setae  usually  more  or  less  straight,  usually  of  two 
different  lengths,  longer  ones  usually  less  than  one-half  the  height  of  the 
head;  warts  bearing  setae  of  two  varying  lengths,  those  on  annulet  4 
being  among  the  shortest  setae. 

SPECIES  OF  PRIOPHORUS 

1  (2)  Front  with  a  distinct  blackish  or  fuscous  spot;  vertex  with  a  dorso-mesal  fuscous  spot 
occupying  nearly  the  entire  space  between  vertical  furrows;  body  never  pinkish  but 
whitish;  head  caudad  of  ocellarae  fuscous;  body  dorsad  of  spiracular  lines  from  meso- 
thorax  to  penultimate  segment  olivaceous  or  grayish,  color  becoming  dilute  on  caudal 
segments;  third  abdominal  segment  with  following  setal  map:  4-5,  4,  5, 1,  3,  6,  8,  12, 
13,  8-9;  maxillary  palpi  2,  (3,  4),  1;  in  younger  specimens  dorsal  grayish  shade  con- 
fined to  cephalic  segments;  on  hazel;  length,  15  mm.;  width  of  head,  1.5  mm.;  M-109. 

modestius  MacGillivray. 

2(1)  Front  without  a  distinct  blackish  or  fuscous  spot,  but  with  a  light  or  pale  brown  spot; 
vertex  with  a  dorso-mesal  fuscous  or  blackish  spot,  not  nearly  occupying  the  entire 
space  between  vertical  furrows;  body  sometimes  pinkish;  not  on  hazel 3. 

3(4)  Head  brown;  vertex  with  blackish  spot  occupying  about  one-half  the  distance  between 
vertical  furrows;  body  pinkish;  head  with  blackish  spot  caudad  of  ocellarae;  dorsum  of 
mesothorax  to  first  abdominal  segment  shaded  gray,  prothorax  whitish;  third 
abdominal  segment  with  the  following  setal  map:  5,  4,  4,  1,  3,  5,  5,  10,  10-12,  6-2; 
maxillary  palpi,  2,  (3,  4),  1;  in  younger  specimens  body  whitish;  length,  14  mm.; 
width  of  head,  1.2  mm.;  on  Salix;  Y-154-1-2 palliolatus  MacGillivray.* 

4(3)  Head  pale  brown;  vertex  on  dorso-meson  with  blackish  spot  occupying  two-thirds 
the  distance  between  vertical  furrows;  spot  also  caudad  of  ocellarae;  body  not 
pinkish  but  whitish,  dorsad  of  spiracular  lines  from  mesothorax  to  penultimate 

*This  species  was  described  as  Trichiocampus  palliolatus  n.  sp.  by  Dr.MacGillivray  in  the 
Entomological  News,  vol.  XXXII,  1921,  page  49,  but  the  characters  of  the  larva  place  it  in  the 
genus  Priophorus.  Upon  reexamination  of  the  adult  specimens,  Dr.  MacGillivray  agrees 
with  me  in  the  change  I  here  make. 


74  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [392 


segment  distinctly  and  uniformly  olivaceous-gray;  third  abdominal  segment  with 
following  setal  map:  5-6,  5,  5,  1-2,  3,  6,  6,  10,  15,  8-9;  maxillary  palpi,  2,  3,  (4,  1); 
in  younger  specimens  black  spots  on  head  larger  and  olivaceous  shade  on  dorsum  of 
body  restricted  to  cephalic  segments;  length,  16  mm.;  width  of  head,  1.6  mm.; 
on  Prunus  virginicus;  Y-138-3.  (This  species  resembles  P.  solitaris  according  to  Dyar's 
description  but  the  latter  feeds  on  Alnus, Priopkorus  sp.  1. 

Cladius  Rossi 

Larvae  rather  small;  length  less  than  15  mm.;  body  slightly  flattened, 
greenish  or  yellowish  green;  never  with  spots  or  shaded  on  dorsal  half;  annu- 
let 1  with  a  transverse  row  of  several  setae,  annulet  2  with  two  warts  bearing 
5-6  setae,  annulet  3  with  three  warts,  dorsal  two  bearing  6-7  setae,  ventral 
with  10  setae;  postsupraspiracular  tubercles  with  5-6  setae;  subspiracular 
lobe  with  14-17  setae,  surpedal  lobe  with  10  setae;  setae  usually  straight, 
usually  of  two  lengths,  longer  ones  less  than  half  the  height  of  head;  setae 
on  annulet  1  among  the  shortest. 

Cladius  pectinicornis  Fourcroy. — Length,  12-14  mm.;  head  pale  brown- 
ish or  yellowish,  microscopically  verrucose,  with  brownish  spots;  front 
touched  with  light  brown;  body  hairy,  uniformly  greenish  or  greenish 
yellow;  third  abdominal  segment  with  the  following  setal  map:  5-6,  5,  6, 
1,  5-6,  6,  7, 10,  14-17,  10;  maxillary  palpi,  (2,  3),  1,  4;  on  Rosa;  Y-3,  M-244. 

Subfamily  Nematinae 

Larvae  (Fig.  18)  small  to  moderately  large;  body  cylindrical,  slender,  or 
abdomen  increasing  in  diameter;  segmentation  and  annulation  usually 
distinct;  third  abdominal  segment  with  4,  5  or  6  annulets,  annulets  1,  2,  3, 
or  1,  2,  4,  or  more  usually  2  and  4,  setiferous;  larvapods  present  on  abdom- 
inal segments  2-7  and  10,  setiferous  or  sometimes  glabrous;  ventral  glands 
present  on  the  meson  of  abdominal  segments  1-7;  thoracic  legs  normal  in 
form;  body  uniformly  greenish  or  darker  colored,  striped  or  spotted, 
tuberculate,  setiferous  or  smooth;  antennae  with  four  segments,  conical, 
subconical,  limpet-shaped,  or  flattened;  antennal  segments  sometimes 
incomplete  or  in  part  fused  together;  tenth  abdominal  tergum  with  or 
without  a  pair  of  caudal  protuberances;  glandubae  sometimes  distinct, 
conspicuous,  and  stalked;  spiracles  winged  or  not;  larvae  free  leaf -feeders, 
gall-makers,  and  leaf-rollers. 

The  Nematinae  is  a  large  subfamily  of  several  genera  and  numerous 
species  and  is  characterized  by  the  coalescence  of  the  cells  2d  A  and  3d  A 
due  to  the  atrophy  of  the  free  part  of  the  3d  anal  vein.  The  absence  of  the 
radial  cross-vein  and  the  cell  1st  2d  A  distinguishes  the  adults  of  this 
subfamily  from  those  of  the  Hoplocampinae  and  Cladiinae  respectively. 
Rohwer  (1912),  who  would  unite  the  Nematinae,  Hoplocampinae,  and 
three  genera  of  the  Cladiinae  in  one  subfamily,  Nematinae,  states  that  the 


393]  LARVAE  OF  THE  TENTHREDIN01DEA—YUASA  75 

subfamily  contains  two  types  of  larvae  and  that  most  of  the  aberrant  larvae 
belong  to  his  tribe  Hemichroini.  It  may  be  pointed  out  that  the  Nema- 
tinae  as  denned  by  MacGillivray  also  contains  two  types  of  larvae,  which 
are  separable  on  the  presence  or  absence  of  the  caudal  protuberances  on 
the  ultimate  segment.  There  are,  however,  other  morphological  and 
biological  characters  of  the  larvae  which  suggest  that  this  subfamily  con- 
tains a  number  of  genera  of  wide  diversity,  and  that  such  genera  as  Ptero- 
nidea  and  Pontania  might  profitably  be  subdivided  into  more  genera. 

GENERA  OF  NEMATINAE 

1(18)     Tenth  abdominal  tergum  without  caudal  protuberances 2. 

2(11)  Antennae  conical  or  subconical,  antennal  segments  2  and  3  always  complete,  segment 
4  peg-like  or  conical,  at  least  as  long  as  wide  at  proximal  end;  third  abdominal 

segment  always  with  six  annulets 3. 

3(4)      Annulets  2  and  4  glabrous;  larvapods  glabrous;  glandubae  obsolete;  thoracic  legs 

with  coxae  in  part  always  colored  brownish Nematus  Panzer. 

4(3)      Annulets  2  and  4  not  glabrous;  larvapods  usually  not  glabrous;  glandubae  usually 

not  obsolete;  thoracic  legs  with  coxae  usually  in  part  not  colored 5. 

5(6)  Antennae  with  segment  3  ring-like,  its  cephalic  portion  subequal  in  length  to  caudal 
portion,  segment  2  complete,  its  cephalic  portion  not  reduced  to  a  mere  line;  body 
increasing  in  diameter  to  abdominal  segments  5-6;  spiracles  usually  winged;  larva- 
pods glabrous  or  with  2-4  or  more  setae  as  viewed  from  lateral  aspect. 

Pristiphora  Latreille. 

6(5)      Antennae  with  segment  3  not  ring-like,  its  cephalic  portion  not  subequal  in  length 

to  caudal  portion;  segment  2  usually  complete  but  its  cephalic  portion  reduced  to  a 

mere  line 7. 

7(8)  Body  increasing  in  diameter  to  abdominal  segments  5-6,  not  uniformly  cylindrical; 
spiracles  usually  winged;  larvapods  with  4-6  setae  as  viewed  from  lateral  aspect. 

Diphadnus  Hartig. 
8(7)      Body  not  increasing  in  diameter  to  abdominal  segments  5-6  but  uniformly  cylindrical; 

spiracles  never  winged;  larvapods  with  1-2  setae  as  viewed  from  lateral  aspect 9. 

9(10)  Thorax  distinctly  swollen;  head  pale  brownish  green;  maxillary  palpi  with  segment  2 
as  long  on  its  lateral  aspect  as  on  its  mesal  aspect;  legs  with  femur  and  tibia  con- 

colorous  with  body,  whitish;  body  with  dorsum  not  shaded  bluish  green 

Pteronidea  Rohwer  (in  part). 

10(9)      Thorax  never  distinctly  swollen;  head  not  pale  brownish  green  but  blackish;  maxillary 

palpi  with  segment  2  three  times  as  long  on  its  lateral  aspect  as  on  its  mesal  aspect; 

legs  with  femur  and  tibia  not  concolorous  with  body  but  blackish;  body  with  dorsum 

shaded  bluish  green Lygaeonematus  Konow. 

11(2)  Antennae  not  conical  or  subconical,  but  flattened;  antennal  segments  2  and  3  not 
always  complete,  segment  4  never  peg-like  or  conical,  never  as  long  as  wide  at 

proximal  end;  third  abdominal  segment  not  always  with  six  annulets 12. 

12(13)     Segments  with  four  annulets,  annulets  1,  2,  and  3  setiferous;  gall-makers 

Pontonia  Costa  (in  part) . 

13(12)     Segments  with  more  than  four  annulets,  annulet  1  not  setiferous;  not  gall-makers. .  14. 

14(15)     Segments  with  five  annulets,  annulets  2  and  3  setiferous;  antennae  with  all  segments 

fused  together;  larvapods  with  two  setae  as  viewed  from  lateral  aspect;  body-setae 

very  long M kronematus  Konow. 


76  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [394 

15(14)  Segments  with  five  or  six  annulets,  annulets  2  and  4  setiferous;  antennae  usually  not 
with  all  segments  fused  together;  larvapods  usually  with  many  more  than  two 
setae  as  viewed  from  lateral  aspect;  setae  on  body  not  very  long;  gland ubae  usually 
conspicuous  and  stalked 16. 

16(17)  Segments  with  six  annulets;  larvapods  with  7-10  setae  as  viewed  from  lateral  aspect; 
surpedal  areas  at  least  in  part  always  marked  with  gray;  latus  of  abdomen  never 
with  numerous  brownish  spots;  tenth  abdominal  tergum  sometimes  distinctly 
pointed  and  produced  caudad  and  with  many  conspicuous  glandubae  near  the  caudal 
margin;  larvae  usually  feeding  on  monocotyledonous  plants. .  .Packynematus  Konow. 

17(16)  Segments  with  five  annulets;  larvapods  with  3-5  setae  as  viewed  from  lateral  aspect; 
surpedal  areas  not  marked  with  gray;  latus  of  abdomen  sometimes  with  numerous 
brownish  spots;  tenth  abdominal  tergum  never  distinctly  pointed  and  produced 
caudad ;  larvae  usually  feeding  upon  willow Amauronematus  Konow  (in  part) . 

18(1)      Tenth  abdominal  tergum  with  a  pair  of  caudal  protuberances 19. 

19(20)  Gall-makers  and  leaf-rollers;  segments  with  four  annulets;  annulets  1,  2,  and  3 
setiferous;  antenae  flattened;  body  setae  more  than  twice  as  long  as  spiracles; 
caudal  protuberances  normal  in  form  and  position  or  rudimentary  or  borne  on  a 
small  caudo-mesal  projection,  if  normal  in  form  and  position,  the  tergum  with 
paired   colored   markings Pontania   Costa    (in   part). 

20(19)  Free  leaf-feeders;  segments  usually  with  five  or  six  annulets,  if  four,  annulets  2  and  4 
usually  setiferous;  antennae  conical  or  flattened 21. 

21(22)  Antennae  conical,  segment  2  complete,  segment  3  ring-like,  its  cephalic  portion 
subequal  in  length  to  caudal  portion;  body  on  latus  with  eleven  conspicuous  blackish- 
brown  spots,  surpedal  and  subspiracular  areas  of  abdominal  segments  1-9  and  venter 
between  larvapods  of  abdominal  segments  2-8  similarly  marked;  spiracles  not  winged; 
caudal  protuberances  of  ultimate  segment  small,  blunt,  not  longer  than  wide  at 
proximal  end;  segments  with  five  or  four  annulets,  with  annulets  2  and  3  or  2  and  4 
setiferous Croesus  Leach. 

22(21)  Antennae  conical  or  flattened;  if  conical,  segment  3  not  ring-like  but  reduced  in  length 
on  cephalic  aspect;  body  not  marked  as  in  Croesus;  spiracles  winged  or  not  winged; 
caudal  protuberances  of  ultimate  segments  not  blunt,  minute,  but  usually  much 
longer  than  wide  at  proximal  end 23. 

23(24)  Segments  apparently  with  five  annulets;  annulets  2  and  3  setiferous;  antennae 
flattened,  with  segment  3  complete;  body-setae  subequal  in  length  to  spiracles;  smaller 
larvae,  length,   13-15  mm Amauronematus  Konow  (in  part). 

24(23)  Segments  with  four  or  six  annulets;  annulets  2  and  4,  rarely  1,  2,  and  3,  setiferous; 
antennae  conical  or  flattened,  segment  3  complete  or  incomplete;  body-setae  often 
longer  than  the  length  of  abdominal  spiracles;  small  to  moderately  large  larvae, 
length,    15-23   mm Pteronidea    Rohwer   (in   part). 

DlPHADNTJS  HARTIG 

Larvae  small,  greenish;  length  less  than  14  mm.;  body  cylindrical,  in- 
creasing in  size  to  abdominal  segments  5-6,  tapering  at  each  end;  thorax  not 
swollen;  tenth  abdominal  tergum  without  a  pair  of  caudal  protuberances; 
third  abdominal  segment  with  six  annulets,  annulets  2  and  4  setiferous; 
spiracles  distinctly  and  usually  equally  winged;  head  marked  with  black  or 
brown  streaks  along  epicranial  stem  and  dorsad  of  ocellarae;  somewhat 
compressed  cephalo-caudad ;  labrum  with  median  emargination  broad  and 
deep  and  with  median  longitudinal  depression;  antennae  distinctly  conical, 


395]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  77 

with  four  segments,  segment  1  incomplete,  segment  2  usually  complete 
tho  reduced  to  a  mere  line  on  cephalic  part,  segment  3  narrowed  on  cepha- 
lic part,  segment  4  short,  conical,  or  peg-like;  larvapods  setiferous,  setae 
4-6  in  number  as  viewed  from  lateral  aspect;  anal  larvapods  rather  large; 
glandubae  sessile;  cuticle  microscopically  spinulate;  suranal  and  subanal 
lobes  with  numerous  setae;  larvae  free  leaf -feeders. 

Diphadnus  appendlculatus  Hartig. — Length,  13  mm.;  width  of  head, 
1.35  mm.;  body  green,  venter  glossy  white;  tenth  abdominal  tergum  not 
marked;  head  greenish  white  with  blackish  brown  streak  along  epicranial 
stem,  except  near  the  occiput,  and  continuing  to  the  dorsal  two-thirds  of 
front,  vertex  dorsad  of  each  ocellara  not  quite  reaching  the  epicranial 
suture;  surface  of  head  with  minute  brownish  spots;  following  parts 
brown:  mandibles  at  apices,  antennae,  cervical  sclerites,  coxae  at  proximal 
third,  tarsal  claws,  and  spiracles;  setae  minute,  with  conspicuous  calices, 
blackish;  glandubae  smaller  at  distal  end  than  the  calyx  of  seta;  larvapods 
on  cephalic  and  lateral  aspects  with  4-6  setae  and  with  a  single  ventral 
glanduba;  annulation,  1,  (6,  2),  (3,  5),  4;  subspiracular  lobe  with  5-6 
setae  and  without  glandubae;  surpedal  lobe  with  about  4  setae  and  one 
subsessile  glanduba;  on  gooseberry;  Y-158,  -159,  M-128. 

Pristiphora  Latreille 
Larvae  small,  greenish;  length  less  than  15  mm.;  body  cylindrical 
usually  slightly  enlarged  at  abdominal  segments  5-6,  tapering  at  each 
end;  thorax  not  swollen;  tenth  abdominal  tergum  without  the  paired 
caudal  protuberances;  third  abdominal  tergum  with  six  annulets,  annulets 
2  and  4  microscopically  setiferous,  setae  sometimes  obsolete;  annulet  1 
always  longest  and  annulet  3  and  4  always  shortest;  spiracles  usually 
winged,  caudal  wing  usually  much  smaller  than  cephalic;  head  marked 
usually  with  a  blackish  or  brownish  streak  along  epicranial  stem,  surface 
with  minute  brown  spots;  labrum  with  distinct  mesal  emargination  and 
longitudinal  depression;  antennae  conical  or  limpet-shaped,  usually  with 
four  distinct  segments,  segment  1  always  minute,  incomplete  on  caudal 
side,  segment  2  complete,  but  usually  narrower  on  cephalic  side,  segment  3 
uniform  in  length,  segment  4  short,  conical;  larvapods  usually  glabrous 
and  with  a  single  ventral  glanduba,  if  setiferous,  setae  microscopic,  2-4 
in  number  as  viewed  from  side;  anal  larvapods  rather  conspicuous,  glandu- 
bae sessile  or  stalked;  cuticle  microscopically  spinulate,  suranal  and 
subanal  lobes  with  numerous  setae;  tenth  abdominal  tergum  as  seen 
from  side  notched  dorsad  of  suranal  lobe;  free  leaf -feeders. 

SPECIES  OF  PRISTIPHORA 
1(8)      Larvapods  setiferous;  antennae  always  conical;  head  always  with  a  brownish  streak 
dorsad  of  each  ocellara;  spiracles  always  with  cephalic  wing  distinctly  larger  than 


78  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (396 

caudal  wing;  setae  with  calices  surrounded  by  minute  brownish  areas;  giandubae 
always  sessile,  sometimes  microscopic,  diameter  never  more  than  half  the  diameter 
of  calices  of  setae 2. 

2(3)  Giandubae  minute  but  distinct,  about  one-third  as  large  as  calices  of  setae  or  micros- 
copic in  smaller  specimens;  annulation,  1,  (5,  6),  2,  3,  4;  subspiracular  area  with  3-4 
setae;  surpedal  area  with  3-4  setae;  larvapods  with  2-4  setae  as  viewed  from  side; 
head  light  brownish-green,  marked  with  fuscous  streaks  on  both  sides  of  entire 
length  of  epicranial  stem,  front  with  dorsal  two-thirds  light  brown;  following  parts 
light  brown:  labrum,  antennae,  mandibles,  cervical  sclerites,  tarsal  claws,  and  spir- 
cles;  body  greenish,  caudal  segments  pinkish  or  bluish,  dorsal  vessel  dark  green  with 
distinct  fine  white  line  on  eash  side;  Length,  14  mm.;  on  Salix;  Y- 143-2-2,-155,  M-96. 

murtfeldtiae  Marlatt. 

3(2)      Giandubae  microscopic,  difficult  to  detect 4. 

4(5)  Second  annulet  of  abdominal  segments  always  longer  than  either  fifth  or  sixth 
annulet;  larvapods  with  about  two  setae  as  viewed  from  side;  subspiracular  areas 
with  4-5  setae,  surpedal  areas  with  4  setae;  annulation,  1,  (5,  6),  2,  4,  3;  on  birch; 
M-24 Pristiphora  sp.  1. 

5(4)  Second  annulet  of  abdominal  segments  always  shorter  than  either  annulet  5  or  6; 
larvapods  with  1-2  or  2-4  setae  as  viewed  from  side;  subspiracular  areas  with  four 
setae;  on  alder  or  willow 6. 

6(7)  Larvapods  with  1-2  setae  as  viewed  from  side;  annulation  1,  2,  (4,  5,  6),  3;  surpedal 
areas  with  3-5  setae;  body  green,  cylindrical;  head  pale  brownish-green,  marked  with 
brown  streak  along  entire  length  of  epicranial  stem  and  dorsal  two-thirds  of  front 
and  vertex,  narrowly  dorsad  of  each  ocellara;  following  parts  brown:  antennae, 
labrum,  mandibles,  maxillary  palpi,  cervical  sclerites,  tarsal  claws,  and  spiracles; 
antennae  conical,  segment  4  short,  conical;  spiracle  with  cephalic  wing  distinctly 
longer  than  caudal;  setae  without  brown  areas  surrounding  calices;  giandubae 
minute,  sessile,  microscopic;  M-74 Pristiphora  sp.  2. 

7(6)  Larvapods  with  2-4  setae  as  viewed  from  side;  surpedal  areas  with  3-5  setae;  annula- 
tion, 1,  2,  6,  5,  4,  3;  on  wolly  willow;  M-90 Pristiphora  sp.   3. 

8(1)  Larvapods  glabrous;  antennae  conical  or  limpet-shaped;  head  with  or  without  a  dark 
streak  dorsad  of  each  ocellara;  spiracles  winged  or  not  winged,  if  winged,  wings 
subequal  in  size,  or  cephalic  wings  larger  than  caudal;  setae  usually  with  calices 
surrounded  by  minute  but  distinct  brownish  areas;  giandubae  sessile  or  stalked, 
sometimes  microscopic 9. 

9(10)  Head  distinctly  and  uniformly  brownish;  spiracles  indistinctly  winged;  all  setae 
ventrad  of  subdorsal  lines  with  calices  surrounded  by  minute  brownish  areas;  an- 
tennae conical;  giandubae  subequal  to  calices  in  diameter;  annulation,  1, 5, 6, 2, 3, 4; 

on  birch;  M-132 Pristiphora  sp.  4. 

10(9)      Head  never  distinctly  and  uniformly  brownish 11. 

11(12)  Body  on  dorso-meson  from  prothorax  to  fifth  abdominal  segment  with  a  distinct 
blackish  line;  spiracles  winged,  cephalic  wings  usually  larger  than  caudal;  all  setae 
ventrad  of  subdorsal  lines  with  calices  surrounded  by  minute  brownish  areas;  an- 
tennae conical;  giandubae  minute,  about  half  as  large  as  calices  in  diameter;  head 
with  distinct  line  along  epicranial  stem;  vertex  without  a  dark  streak  dorsad  of  each 

ocellara;  annulation,  1, 2,  (5, 3, 4, 6)  or  1, 2,  (3, 4, 5, 6);  on  Prunus;  M-128 

Pristiphora  sp.  5. 

12(11)  Body  on  dorso-meson  from  prothorax  to  fifth  abdominal  segment  without  a  distinct 
blackish  line 13. 

13(14)  Head  entirely  pale  or  light  brown;  vertex  without  dark  streak  along  epicranial  stem. 
antennae  distinctly  conical;  spiracles  winged,  wings  subequal  in  size;  setae  never  with 


397]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  79 

calices  surrounded  by  distinct  brownish  areas;  glandubae  probably  obsolete,  micro- 
scopic; annulation,  1,  5,  6,  2,  3,  4;  on  oak;  M-20 Pristiphora  sp.  6. 

14(13)  Head  never  entirely  pale  or  light  brown;  vertex  always  with  a  dark  streak  along 
epicranial  stem,  sometimes  indistinct  but  never  entirely  wanting 15. 

15(22)  Spiracles  winged ;  setae  ventrad  of  spiracular  lines  with  calices  surrounded  by  distinct 
minute  brownish  areas;  antennae  always  conical;  vertex  with  or  without  a  dark 
streak  dorsad  of  each  ocellara 16. 

16(19)  Spiracles  with  cephalic  wings  always  larger  than  caudal;  glandubae  always  sessile; 
gland os  microscopic,  difficult  to  detect;  setae  on  latus  dorsad  of  spiracular  lines 
with  calices  surrounded  or  not  surrounded  by  distinct  brownish  areas 17. 

17(18)  All  setae  on  latus  dorsad  of  spiracular  lines  with  calices  surrounded  by  brownish 
areas;  vertex  dorsad  of  each  ocellara  with  a  brownish  streak;  annulation,  1,  (5,  6), 
2,  4,  3;  body  green;  head  marked  as  in  P.  bivittata;  length  of  body,  12-13  mm.;  on 
Salix;    M-72 sychophanta    Walsh. 

18(17)  All  setae  on  latus  dorsad  of  spiracular  lines  with  calices  not  surrounded  by  brownish 
areas;  vertex  dorsad  of  each  ocellara  without  a  brownish  streak,  uniformly  pale; 
annulation,  1,  (2,  5,  6),  4,  3;  body  enlarged  on  abdominal  segments  5-6,  greenish, 
with  dorsal  vessel  dark  green  with  white  line  on  each  side;  head  greenish  with  brown- 
ish streaks  along  entire  length  of  epicranial  stem,  expanding  on  the  dorsal  half  of 
front;  following  parts  brown:  labrum,  mandibles,  antennae,  cervical  sclerites,  tarsal 
claws,  and  spiracles;  antennae  conical,  segment  4  elongate,  conical;  on  Spiraea  latifolia 
and  S.  tomentosa;  M-4 Pristiphora  sp.  7. 

19(16)  Spiracles  with  wings  subequal  in  size;  glandubae  stalked ;  glandos  subequal  in  diameter 
to  calices;  setae  on  latus  dorsad  of  spiracular  lines  never  with  calices  surrounded  by 
distinct  brownish  areas 20. 

20(21)  Vertex  with  a  distinct  dark  streak  dorsad  of  each  ocellara;  annulation,  1, 2,  (5, 6),  4, 3; 
length,  16-17  mm.;  body  cylindrical,  increasing  in  size  to  abdominal  segments  5-6, 
green,  dorsal  vessel  dark  green  with  fine  white  line  on  each  side  of  it;  head  green, 
slightly  brownish,  with  fuscous  streaks;  following  parts  light  brown :  dorsal  two- thirds 
of  front,  labrum,  maxillary  palpi  and  galea,  labial  palpi,  and  cervical  sclerites;  follow- 
ing parts  brown:  antennae,  mandibles,  spiracles,  glandubae,  and  setae;  antennae 
conical,  distinctly  with  four  setae,  segment  4  conical;  spiracles  with  wings;  ven- 
tral glands  subequal  in  size  to  larvapods;  glandos  in  diameter  subequal  to  or  larger 

than  calices  of  setae;  setae  on  dorsum  very  minute;  on  Spirea;  Y,  M-14,-88 

bivittata  Norton. 

21  (20)  Vertex  without  a  distinct  dark  streak  dorsad  of  each  ocellara;  annulation,  1, 2, 6, 5, 3, 
4;  on  Potentilla;  M-10 Pristophora  sp.  8. 

22(15)  Spiracles  not  winged;  setae  ventrad  of  spiracular  lines  never  with  calices  surrounded 
by  distinct  minute  brownish  areas;  antennae  limpet-shaped,  segments  indistinguish- 
ably  fused;  vertex  always  with  a  brown  streak  dorsad  of  each  ocellara;  glandubae 
sessile;  glandos  microscopic,  difficult  to  detect;  annulation,  1,  (2,  5,  6),  (3,  4);  length 
12-13  mm.;  body  green,  with  broad  dark  green  dorsal  vessel  bordered  on  each  side 
by  a  fine  white  line;  head  greenish  brown;  setae  stiff,  comparatively  long,  without 
brown  areas  surrounding  calices;  on  Geum  canadensis;  Y-212.  .Pristiphora  sp.  9. 

MlCRONEMATUS  KONOW 

Larvae  small;  length  less  than  15  mm.;  body  subcylindrical,  tapering 
at  both  ends;  mesothorax  distinctly  and  metathorax  slightly  swollen; 
lateral  lobes  prominent  and  swollen;  segmentation  distinct;  annulation 
indistinct;  third  abdominal  segment  with  five  annulets,  annulets  2  and 


80  ILLINOIS  BIOLOGICAL  MONOGRAPHS  {398 

3  setiferous;  thoracic  legs  spreading  laterad,  normal  in  form;  larvapods 
setiferous,  normal  in  form,  except  the  anal  pair,  which  is  reduced  in  size, 
only  one-half  as  large  as  the  other  pairs;  tenth  abdominal  tergum  with- 
out the  paired  caudal  protuberances;  head  circular,  smaller  than  thorax 
in  width  and  height,  front  flattened;  antennae  apparently  with  four  seg- 
ments, flattened,  all  segments  fused  together;  ventral  glands  very  large; 
setae  sparse,  very  long;  spiracles  not  winged;  suranal  and  subanal  lobes 
multisetif  erous ;  glandubae  subsessile;  free  leaf -feeders. 

Konow  in  1905  listed  three  species  of  Micronematus:  abbreviates, 
califomicus,  and  monogyniae.  The  second  species  properly  belongs  to 
Diphadnus.  Of  the  two  remaining  species,  M.  abbreviates  was  recognized 
in  the  larval  stages  a  long  time  ago  by  Snellen  von  Vollenhoven  (1868). 
This  genus  is  European  and  is  represented  in  North  America  by  a  single 
species,  Micronematus  gregarius  Marlatt.  That  this  species  does  not 
belong  to  Pachynematus  can  be  readily  seen  from  the  structure  and 
biological  characters  of  the  larvae  as  was  suggested  by  Dyar  (1897) 
in  his  original  description  of  the  immature  stages.  Three  facts  distinguish 
this  species  from  all  other  known  species  of  Pachynematus:  (1)  the  larva 
has  five  annulets  instead  of  six;  (2)  the  anal  larvapods  are  very  much  reduced 
in  size;  and  (3)  the  larva  feeds  on  willow  instead  of  grasses.  On  the  other 
hand  M.  gregarius  has  certain  characters  in  common  with  M.  abbreviates 
as  recorded  by  Vollenhoven.  Since  this  species  can  not  be  referred  to 
Pachynematus  or  to  any  other  known  American  genus,  and  since  it  has 
characters  which  are  peculiar  to  Micronematus,  and  since  the  adult 
characters,  according  to  Ashmead  (1898),  would  place  it  in  this  genus, 
this  species  is  here  considered  as  belonging  to  Micronematus.  If  future 
study  should  prove  this  position  untenable,  a  new  genus  should  be  erected. 

Micronematus  gregarious  Marlatt. — Length,  12  mm.;  body  shiny, 
yellowish  white;  alimentary  canal  showing  thru  as  green  tube;  head  pale 
testaceous  with  a  broad  blackish  band  across  the  front  between  ocellarae 
and  a  narrow  band  dorsad  of  each  ocellara  to  and  along  vertical  furrow; 
mouth-parts,  cervical  sclerites,  and  legs  except  coriae  brownish;  abdominal 
segments  1-8  with  postspiracular  and  subspiracular  areas  swollen,  mound- 
like, and  tinted  fuscous;  abdominal  segments  2-7  with  colored  postspiracu- 
lar areas  larger  than  subspiracular  areas;  those  on  segments  1  and  8  much 
smaller;  thoracic  segments  with  two  colored  patches  on  latus,  one  larger 
and  more  ventral  than  the  other;  larvapods  with  about  two  setae  on  the 
cephalo-lateral  aspect;  ventral  glands  nearly  three  times  as  large  as  larva- 
pods; setae  slender,  at  least  twice  as  long  as  spiracles;  spiracles  not  winged; 
subspiracular  area  with  two  setae  and  single  glanduba,  surpedal  area 
with  3-4  setae  and  single  glanduba;  larvae  gregarious;  on  Salix;  Y. 


399]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  81 

Lygaeonematus  Konow 

Larvae  comparatively  speaking  moderately  large,  length  18-20  mm.; 
body  cylindrical,  tapering  uniformly  and  slightly  caudad;  thorax  not 
swollen;  abdomen  never  swollen;  dorsum  grayish  green  and  venter  pale, 
head  shiny  black,  only  slightly  narrower  than  thorax;  antennae  conical, 
with  four  distinct  segments,  segment  1  minute,  incomplete,  and  with  single 
sensory  pit,  segments  2  and  3  narrower  on  cephalic  part  than  on  caudal 
part,  segment  4  conical;  labrum  with  mesal  emargination  shallow  and  broad; 
maxillae  with  galea  larger  than  labial  palpi;  maxillary  palpi  with  segment  2 
three  times  as  long  on  lateral  margin  as  on  mesal;  third  abdominal  segment 
with  six  annulets,  annulet  1  largest,  annulets  2  and  4  setiferous;  larvapods 
well  developed,  setiferous,  with  1-2  setae  and  single  ventral  glanduba; 
glandubae  sessile;  glandos  smaller  than  calyx  of  a  seta;  ventral  glands 
subequal  to  or  larger  than  larvapods  in  size;  spiracles  not  winged;  tenth 
abdominal  tergum  as  seen  in  profile  not  notched  dorsad  of  suranal  lobe  and 
without  caudal  paired  protuberances;  setae  usually  arising  from  minute 
fleshy  mound-like  protuberances;  cuticle  microscopically  spinulate;  free 
leaf-feeders. 

Lygaeonematus  erichsoni  Hartig. — Length,  18-20  mm.;  body  somewhat 
shiny,  greenish  gray  dorsad  of  spiracular  lines,  ventrad  of  them  opaque 
bluish- white,  head  black;  following  parts  fuscous  to  blackish:  mouth-parts, 
cervical  sclerites,  femur,  tibia,  and  claws;  following  parts  grayish:  surpedal 
areas,  coxa,  and  trochanter  in  part,  swellings  between  legs,  and  abdominal 
surpedal  areas  faintly;  annulation,  1,  2,  6,  (3,  5,  4);  glandos  half  as  large 
in  diameter  as  calices  of  adjacent  setae;  surpedal  areas  on  abdomen  with 
8-10  setae  and  two  glandubae;  subspiracular  area  with  6-7  setae,  usually 
without  glandubae;  cuticle  with  distinct  microscopic  brownish  spinulae; 
on  larch;  Y-162,  M-105,  -165. 

Pachynematus  Konow 
Larvae  comparatively  speaking  moderately  large;  length,  15-23  mm.; 
body  cylindrical,  tapering  uniformly  and  distinctly  caudad;  thorax  rarely 
and  abdomen  never  swollen;  third  abdominal  segment  with  six  annulets, 
annulets  2  and  4  setiferous,  annulet  1  longest,  annulet  4  usually  shortest; 
tenth  abdominal  tergum  without  a  pair  of  caudal  protuberance,  and  without 
a  notch  dorsad  of  suranal  lobe  as  seen  in  profile;  the  tergum  sometimes 
produced  distinctly  caudad  and  pointed;  suranal  and  subanal  lobes  with 
numerous  setae;  head  brownish  or  greenish,  sometimes  with  fuscous 
streak  along  epicranial  stem,  semiglobose,  subequal  in  width  to  thorax 
or  only  slightly  narrower;  labrum  with  median  longitudinal  depression, 
cephalic  emargination  shallow;  maxillae  with  galea  always  larger  than 
labial  palpi,  sometimes  more  than  twice  as  large;  antennae  with  four  seg- 
ments, flattened,  never  distinctly  conical,  segment  1  usually  minute,  in- 


82  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [400 

complete,  segments  2  and  3  with  cephalic  parts  distincty  reduced  to  mere 
lines,  sometimes  all  four  segments  fused;  larvapods  always  setiferous,  with 
8-11  setae  on  cephalic  and  lateral  aspects  and  a  single  ventral  glanduba; 
glandubae  conspicuous,  cylindro-conical,  at  least  twice  as  long  as  wide 
at  proximal  end;  spiracles  usually  not  winged,  if  winged,  rather  indistinctly; 
setae  stiff,  brown,  arising  from  fleshy  mound-like  minute  tubercles;  in 
younger  specimens  third  abdominal  segment  with  five  annulets,  annulets 
1,  2,  and  3  with  stiff  brown  setae;  glandubae  obsolete;  cuticle  microscopi- 
cally spinulate;  larvae  usually  feed  upon  grasses. 

This  generic  description  is  based  upon  two  identified  and  several  un- 
identified species.    The  known  species  can  be  separated  as  follows: 

SPECIES  OF  PACHYNEMATUS 

Head  with  narrow  fuscous  or  blackish  streak  along  epicranial  stem  and  vertical  furrows; 
tenth  abdominal  tergum  with  a  broad  fuscous  streak  on  the  meson  and  the  caudal  margin 
produced  distinctly  caudad  and  bluntly  pointed,  with  many  conspicuous  glandubae;  antennae 
with  four  fused  segments;  annulation,  (2, 1),  6,  (3, 4,  5);  larvapods  with  7-9  setae  on  cephalic 
and  1  seta  on  lateral  aspect;  subspiracular  lobe  with  5-6  setae  and  1-2  glandubae;  surpedal 
lobe  with  5-7  setae  and  1-3  glandubae;  body  on  dorso-lateral  lines  with  narrow,  interrupted 
longitudinal  fuscous,  bands;  head  as  wide  as  thorax;  length,  20  mm.  width  of  head,  2  mm.; 

on  Carex;  Y-150 subalbattu  Norton. 

Head  with  narrow  fuscous  or  blackish  streak  along  epicranial  stem  and  vertical  furrows; 
tenth  abdominal  tergum  without  a  broad  fuscous  streak  on  the  meson,  the  caudal  margin 
only  slightly  produced  caudad,  rounded,  with  many  glandubae;  antennae  with  four  segments 
not  fused ;  annulation,  (1, 2),  6,  (3, 4, 5) ;  larvapods  with  about  ten  setae  on  cephalic  and  one  se- 
ta on  lateral  aspect;  subspiracular  lobe  with  about  six  setae  and  a  single  glanduba;  surpedal 
lobe  with  six  setae  and  three  glandubae;  head  as  wide  as  thorax;  length,  16  mm.;  width  of 
head,  1.6  mm.;  on  Carex;  Y-177 repertus  MacGillivray. 

Nematus  Panzer 

Larvae  comparatively  small,  length  about  10  mm.;  body  cylindrical, 
uniform  in  diameter  thruout  the  entire  length  excepting  the  caudal  end, 
where  it  is  tapering,  dull  green,  apparently  glabrous;  annulation  indis- 
tinct; third  abdominal  segment  with  six  annulets,  annulets  glabrous, 
formula:  1,  5,  2,  6,  3,  4;  thoracic  legs  normal  in  form;  coxa  usually  fus- 
cous on  proximal  half;  larvapods  small,  diminishing  in  size  gradually  on 
the  caudal  segments,  not  setiferous;  ventral  glands  subequal  in  size  to  larva- 
pods; tenth  abdominal  tergum  without  a  pair  of  caudal  protuberances, 
with  a  notch  dorsad  of  suranal  lobe  as  seen  in  profile,  caudal  margin  trun- 
cate or  slightly  emarginate  on  the  meson,  not  produced;  suranal  lobe  with 
several  minute  setae  on  ventral  aspect;  subanal  lobe  with  moderately 
numerous  minute  setae;  abdomen  with  lateral  lobes  inconspicuously 
swollen;  head  circular  in  outline,  rounded  in  profile  on  dorsal  half,  front 
flattened;  ventral  half  of  head  with  several  longer  and  larger  setae;  dorsal 
half  nearly  glabrous  or  with  microscopic  setae;  vertex  usually  with  a  fuscous 


401]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  83 

streak  caudad  and  dorsad  of  each  oceJlara;  antennae  four-segmented, 
subconical  or  sublimpet-shaped,  sometimes  in  part  fused;  segment  1 
minute,  segments  2  and  3  reduced  to  mere  line  on  cephalic  aspect,  segment 
4  minute,  subconical;  mouth-parts  and  cervical  sclerites  fuscous  to  black- 
ish; maxillary  palpi  with  two  distal  segments  distinctly  smaller  than 
segment  2,  which  is  sometimes  longer  than  all  the  other  segments  taken 
together;  galea  larger  than  labial  palpus;  sericos  distinct,  circular;  sub- 
spiracular  and  surpedal  lobes  with  a  few  microscopic  setae;  glandubae 
probably  microscopic,  usually  obsolete;  spiracles  usually  winged;  cuticle 
microscopically  spinulate;  free  leaf-feeders. 

SPECIES  OF  NEMATUS 

1(4)  Vertex  with  a  fuscous  streak  caudad  and  dorsad  of  each  ocellara;  maxillary  palpi 
with  segment  2  shorter  than  all  the  other  segments  taken  together 2. 

2(3)  Vertex  with  fuscous  streaks  extending  dorsad  of  vertical  furrows;  antennae  with  all 
segments  fused  and  almost  completely  filling  antafossae;  spiracles  distinctly  winged; 
tenth  abdominal  tergum  with  caudal  margin  shallowly  emarginate  on  the  meson; 
head  with  dorsal  half  entirely  glabrous ;  length,  1 1  mm. ;  on  oak ;  M-2 1 . .  chloreus  Norton. 

3(2)  Vertex  with  fuscous  streaks  not  extending  dorsad  of  vertical  furrows;  antennae  with 
all  segments  distinct,  but  not  nearly  completely  filling  antafossae;  spiracles  not 
distinctly  winged;  tenth  abdominal  tergum  with  caudal  margin  not  emarginate  on  the 
meson;  head  with  dorsal  half  sparsely  setiferous;  length,  9  mm.;  Y-133.  Nematus  sp.  1. 

4(1)  Vertex  without  a  fuscous  streak  caudad  and  dorsad  of  each  ocellara;  maxillary  palpi 
with  segment  2  slightly  longer  than  all  the  other  segments  taken  together;  antennae 
with  four  distinct  segments;  spiracles  winged;  length,  10.5  mm.;  on  oak;  M-2. 

Nematus  sp.  2 

Croesus  Leach 

Larvae  moderately  large,  length  about  25  mm.,  body  cylindrical  tapering 
caudad  on  abdominal  segments  7-10  and  also  at  cephalic  end  of  prothorax; 
segmentation  distinct;  annulation  indistinct;  third  abdominal  segment 
with  four  or  five  annulets,  annulets  2  and  3  setiferous;  tenth  abdominal 
tergum  with  a  pair  of  low,  conical,  bluntly  rounded  caudal  protuberances, 
usually  as  wide  as  or  wider  than  high;  head  flattened  on  front,  rounded, 
shiny  black;  antennae  distinctly  conical  with  four  segments:  segment  1 
incomplete,  three  times  as  long  as  wide,  segments  2  and  3  usually  complete 
and  not  reduced  to  mere  lines  on  the  cephalic  aspect,  segment  4  peg-like, 
bluntly  pointed,  longer  than  wide  at  proximal  end;  maxillary  palpi  with 
segment  1,  3,  and  4  subequal  in  length,  segment  2  twice  as  long  as  segment 
1 ;  larvapods  setiferous;  spiracles  not  winged,  indistinctly  colored;  glandubae 
subsessile  or  with  a  short  stalk,  very  wide  in  diameter  more  than  three 
times  the  diameter  of  shaft  of  setae;  maxacoria  developed  into  a  distinct 
triangular  swelling  dorso-caudad  of  cardo,  and  covered  with  dark  spinulae. 

Croesus  latitarsus  Norton. — Length,  25  mm.;  annulation,  3,  2,  1,  4  or 
2,  1,  5,  3,  4;  larvapods  with  4-5  setae  and  a  single  glanduba  as  viewed 
from  side,  no  markings;  tenth  abdominal  tergum  with  dark-colored  area 


84  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [402 

contiguous  to  concolorous  suranal  protuberances;  suranal  and  subanal 
lobes  with  numerous  setae,  which  increase  in  length  with  the  distance 
from  the  anus;  body  yellowish  green  or  brownish,  with  colored  patches  on 
subspiracular  and  surpedal  areas  and  on  subdorsal  line  from  mesothorax 
to  ninth  abdominal  segment;  abdominal  segments  2-8  on  ventro-meson 
each  with  a  large  colored  patch;  in  younger  stages  body  fuscous  with 
few  distinctly  delimited  colored  patches  or  none;  M-1,-26,-50,-51,-48. 

Amauronematus  Konow 

Larvae  small  to  moderately  large;  length  15-20  mm.;  body  cylin- 
drical, often  tapering  distinctly  caudad;  latus  with  subspiracular  and 
surpedal  areas  colored  or  with  numerous,  minute  colored  spots;  head 
blackish,  brownish,  or  greenish;  third  abdominal  segment  with  five  annu- 
lets, annulets  2  and  3  or  2  and  4  setiferous;  tenth  abdominal  tergum  with 
or  without  caudal  paired  protuberances;  body  setae  much  longer  or 
shorter  than  the  length  of  spiracles;  larvapods  with  2-3  or  3-5  setae  as 
viewed  from  side;  spiracles  not  winged;  larvae  free  leaf -feeders. 

The  larval  stages  of  five  species  of  Amauronematus  have  been  described 
by  Dyar.  Of  these,  larvae  of  luteotergum,  dyari,  oregonensis,  and  similis 
have  not  been  available  for  study,  but  according  to  Dyar's  descriptions, 
the  last  three  apparently  lack  the  caudal  paired  protuberances.  I  have  a 
large  number  of  larvae  collected  on  willow  by  Dr.  MacGillivray  which 
also  lack  the  paired  caudal  protuberances  and  probably  belong  to  this 
genus.    The  species  may  be  separated  as  follows : 

SPECIES  OF  AMAURONEMATUS 

1  (4)      Tenth  abdominal  segment  with  paired  caudal  protuberances 2. 

2(3)  Abdomen  on  ventro-meson  with  a  row  of  blackish  spots;  caudal  paired  protuberances 
and  head  blackish;  gregarious;  on  alder luteotergum  Norton. 

3(2)  Abdomen  on  ventro-meson  without  a  row  of  blackish  spots;  paired  caudal  protuber- 
ances and  head  not  blackish  but  pale;  solitary;  on  Azalea azaleae  Marlatt. 

4(1)      Tenth  abdominal  segment  without  paired  caudal  protuberances 5. 

5(6)  Mature  and  also  younger  larvae  with  antennae  flattened  and  their  segments  fused 
in  part,  with  no  discernible  or  with  very  small  antacoria;  younger  larvae  (14  mm.  or 
less)  with  annulets  1,  2  and  4  setiferous;  annulets  2  and  4  with  transverse  row  of 
warty  protuberances  each  bearing  2  or  3  stiff  stout  setae;  older  larvae  (14  mm.  or 
more)  without  numerous  brownish  spots  on  dorsum  and  latus  and  without  brownish 
interrupted  and  diffuse  dorso-mesal  and  dorso-lateral  lines;  on  sweet  fern;  M-85. 

Amauronematus  sp.  1. 

6(5)  Mature  larvae  with  antennae  whose  segments  are  all  distinctly  separated  by  distinct 
antacoria;  young  larvae  with  antennae  like  those  of  preceding  species;  younger  larvae 
(14  mm.  or  less)  with  annulets  1,  2,  and  4  setiferous;  annulets  2  and  4  without 
transverse  row  of  warty  protuberances  the  setae  being  minute  and  arranged  singly; 
older  larvae  (14  mm.  or  more)  with  numerous  brownish  spots  on  dorsum  and  latus 
with  brownish,  interrupted,  and  diffuse  dorso-mesal  and  dorso-lateral  lines;  on  willow; 
M-10 virendus  MacGillivray. 


403]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  85 

Another  species,  resembling  the  preceding  very  closely  and,  difficult  to  distinguish  except 
by  the  colored  spots  which  are  more  or  less  darker  and  slightly  more  numerous  than  in 
virendus;  M-l  12 vescus  MacGillivray. 

Pteronidea  Rohwer 

Larvae  small  to  moderately  large;  length  15-25  mm.;  greenish,  often 
spotted  or  banded  transversely  or  longitudinally;  body  cylindrical,  slender, 
uniformly  tapering  caudad,  thorax  rarely  conspicuously  swollen;  head  and 
trunk  setiferous,  often  tuberculate;  head  blackish,  brownish,  or  greenish; 
antennae  with  four  segments,  sometimes  with  segments  in  part  fused, 
conical,  subconical,  or  flattened;  third  abdominal  segment  with  4-6 
annulets,  more  commonly  5-6,  annulets  2  and  4,  rarely  1,  2,  and  3  setiferous; 
tenth  abdominal  tergum  with  or  without  a  pair  of  small  but  distinct  suranal 
caudal  protuberances,  if  without,  body  swollen  on  thorax,  protuberances 
pointed,  bluntly  rounded,  truncate,  or  swollen  at  distal  end;  larvapods 
setiferous,  setae  few  in  number;  spiracles  winged  or  unwinged;  glandubae 
subsessile  or  obsolete;  leaf -feeders,  sometimes  gregarious. 

The  genus  Pteronidea  is  rich  in  number  of  species.  The  author  has 
examined  a  large  number  of  specimens  representing  at  least  thirty  species 
and  including  much  bred  material,  and  has  prepared  the  following  synoptic 
key  for  differentiating  species.  It  may  be  stated  here  that  Pteronidea, 
together  with  a  few  allied  genera,  is  readily  separated  from  all  other  Tenth- 
redinidae  by  the  presence  of  a  pair  of  suranal  caudal  protuberances  on  the 
lateral  portion  of  the  caudal  margin  of  the  ultimate  tergum.  Pteronidea 
thoracica  Harrington  is  unique  in  lacking  the  caudal  paired  protuberances, 
but  is  easily  distinguished  by  its  characteristic,  somewhat  elongate,  tad- 
pole-like body,  and  also  by  its  white  head  and  body  and  its  spreading  legs. 
The  color  and  coloration  and  the  presence  of  setiferous  tubercles  and  their 
arrangement  are  useful  characters  in  separating  species. 

SPECIES  OF  PTERONIDEA 
1(2)      Tenth  abdominal  tergum  without  suranal  processes;  thorax  conspicuously  swollen; 

thoracic  legs  spreading  out  flat  laterad;  body  entirely  greenish  white;  on  Prunus 

virginiana;  Y-141 thoracica  Harrington. 

2(1)      Tenth  abdominal  tergum  with  suranal  processes;  thorax  not  conspicuously  swollen.  3. 

3(50)     Head  black  or  brown;  body  usually  with  numerous  colored  patches 4. 

4(5)      Body  entirely  blackish  with  distinct  yellowish  spots  on  latus;  on  Salix,  Populus 

balsamifera,  etc.;  Y-8.45,  M-104,  M-182,  Y-5-2 ventralis  Say. 

5(4)      Body  not  entirely  blackish,  without  distinct  yellowish  spots  on  latus 6. 

6(7)      Body  entirely  green;  head  light  brown;  suranal  processes  short,  mere  swellings;  on 

Ribes  sp.;  Y-l ribesi  Scopoli  (ultimate  stage) 

7(6)      Body  not  entirely  green;  suranal  processes  usually  distinctly  pointed,  more  than 

mere  swellings 8. 

8(9)      Body  yellowish  with  11  transverse  black  markings  extending  between  subdorsal 

lines  across  the  venter.    Young  collection  55 Pteronidia,  sp.  1. 

9(8)      Body  not  yellowish,  without  1 1  transverse  blackish  markings 10. 


86  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [404 

10(17)  Body  without  numerous  small  tuberculate  areas,  usually  without  fine  longitudinal 
series  of  sub-adjacent  patches;  thorax,  at  least,  always  suffused  on  dorsum  with 
darker  shade 11. 

11(12)  Body  shiny  metallic  fuscous;  dorsum  of  all  segments  grayish  brown;  tenth  abdominal 
tergum  uniformly  black;  Y-132-2-1  (on  Carpinus  caroliniana) ,  Y-132m-l-2  (on 
Mows  alba),  Y-193  (on  Alnus  rugosa), erythrogastra  Norton. 

12(11)  Body  not  shiny  metallic  fuscous;  dorsum  of  none  of  segments  grayish-brown;  tenth 
abdominal  tergum  not  uniformly  black 13. 

13(14)  Abdomen  on  dorso-meson  with  a  fine  longitudinal  line;  tenth  abdominal  tergum 
fuscous  on  dorso-meson;  suranal  processes  distinctly  fuscous;  on  Alnus;  M-114. 

Pteronidea  sp.  2. 

14(13)  Abdomen  on  dorso-meson  without  a  fine  longitudinal  line;  tenth  abdominal  tergum 
not  fuscous  on  dorso-meson;  suranal  processes  not  distinctly  fuscous 15. 

15(16)  Tenth  abdominal  tergum  with  a  fuscous  triangular  mark  on  each  side  of  meson;  head 
more  or  less  uniformly  brown;  on  Salix  rostraia;  Y-169,  C-427-45.  .Pteronidea  sp.  3. 

16(15)  Tenth  abdominal  tergum  without  a  fuscous  triangular  mark  on  each  side  of  meson; 
head  not  uniformly  brown  but  epicranial  stem,  vertex  dorsad  of  ocellarae,  front  in  the 
center,  and  labrum  distinctly  darker;  on  hazel  (?);  M-153 Pteronidea  sp.  4. 

1 7(10)  Body  with  numerous  small  blackish  tuberculate  areas;  sometimes  with  fine  interrupted 
longitudinal  lines  composed  of  irregular  subadjacent  colored  areas;  thorax  on  dorsum 
never  suffused  with  darker  shade 18. 

18(27)  Body  on  dorso-meson  with  a  fine  more  or  less  continuous  black  line  independent  of 
greenish  or  pale  dorsal  vessel,  line  occasionally  faint  but  never  entirely  obsolete; 
latus  usually  with  fine  more  or  less  continuous  longitudinal  lines 19. 

19(20)  Abdomen  on  ventro-meson  with  fuscous  spots;  larvapods  on  cephalic  surpedal 
areas  never  with  fuscous  spots;  on  Alnus;  M-232 Pteronidea  sp.  5. 

20(19)  Abdomen  on  ventro-meson  never  with  fuscous  spots;  larvapods  on  cephalic  surpedal 
areas  often  with  fuscous  spots 21. 

21(24)  Antennae  with  antacoriae  distinct,  not  limited  to  periphery  of  an ta fossae;  antennal 
segment  1  very  minute,  never  more  than  twice  as  long  as  wide;  segment  2  usually 
incomplete,  if  complete,  ventral  portion  never  more  than  a  mere  faint  line;  segment  3 
usually  complete,  cephalic  portion  reduced  to  a  line 22. 

22(23)  Larvapods  on  cephalic  aspect  with  minute  irregular  blackish  or  brownish  spots  near 
setae;  on  Salix;  Y-8.48(?)-l Pteronidea  sp.  6. 

23(22)  Larvapods  on  cephalic  aspect  without  minute  irregular  black  spots  near  setae;  on 
Salix  spp.;  Y-6-1,-6-6,-44-1-1,  M-156  (in  part),  C-140,  C-649 odoratus  Dyar. 

24(21)  Antennae  with  antacoriae  indistinct,  limited  to  periphery  of  antafossae;  antennal 
segment  1  complete,  or  if  incomplete,  never  less  than  twice  as  long  as  wide;  segments 
2  and  3  always  complete,  their  cephalic  and  dorsal  portions  never  reduced  to  mere 
lines;  segment  4  cylindro-conical;  all  four  segments  often  fused  together  in  part  and 
filling  antafossae  almost  completely;  larvapods  on  cephalic  aspect  with  irregular 
black  spots  near  setae,  spots  sometimes  very  minute  but  never  wanting  from  all 
larvapods 25. 

25(26)  Antennae  with  all  4  segments  fused  together  in  part  and  filling  antafossae  almost 
completely;  on  Salix  spp.;  Y-95-1-1,  Y-8.45  (?)s-l-l corneUi  Marlatt. 

26(25)  Antennae  without  all  4  segments  fused  together  in  part;  segment  1  always  dis- 
tinctly separated  from  the  other  segments;  antacorriae  always  distinct;  on  Populus; 
M-156   (in  part) Pteronidea  sp.  7 

27(18)  Body  on  dorso-meson  never  with  a  fine  more  or  less  continuous  black  line  independent 
of  greenish  or  pale  dorsal  vessel;  latus  usually  without  fine  more  or  less  continuous 
longitudinal  lines 28. 


405]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  87 

28(29)  Latus  with  distinct  more  or  less  continuous  longitudinal  lines;  venter  on  meson 
without  black  spots;  C-713 Pteronidea  sp.  8. 

29(28)  Latus  without  distinct  more  or  less  continuous  longitudinal  lines;  venter  on  meson 
usually  with  black  spots 30. 

30(31)  Larvapods  always  with  black  spots  on  cephalic  aspect;  dorsum  with  setiferous 
black  tubercles  more  or  less  uniform  in  size;  abdomen  on  ventro-meson  without 
black  spots;  on  Ribes  sp.;  Y-l;  M-135 ribesi  Scopoli. 

31(30)  Larvapods  never  with  black  spots  on  cephalic  aspect;  dorsum  with  setiferous  black 
tubercles  never  uniform  in  size;  abdomen  usually  with  black  spots  on  ventro-meson.32. 

32(33)  Larvapods  on  abdominal  segments  4-7  usually  with  minute  black  spots  on  mesal 
aspect,  those  on  sixth  abdominal  segment  never  wanting;  abdomen  on  ventro- 
meson  without  black  spots;  on  Salix;  Y-95-1;  M-155  (in  part);  M-140 

Pteronidea  sp.  9. 

33(32)  Larvapods  on  abdominal  segments  4-7  without  minute  black  spots  on  mesal  aspect; 
abdomen  on  ventro-meson  with  black  spots 34. 

34(47)     Abdominal  segments  7-9  on  ventro-meson  with  black  spots 35. 

35(40)  Ninth  abdominal  tergum  with  colored  patches  on  first  three  annulets,  4,  6,  and  4 
patches  respectively 36. 

36(39)     Dorsum  not  shaded  grayish-brown 37. 

37(38)    On  Populus;  G-14;  M-158 efeta  MacGillivray. 

38(37)     On  hazel;  M-110 effusa  MacGillivray. 

39(36)     Dorsum  shaded  grayish-brown;  on  Salix;  Y-8.45(?)-2-l Pteronidea  sp.  10. 

40(35)     Ninth  abdominal  tergum  with  colored  patches  on  first  three  annulets .41. 

41(44)     Colored  patches  on  first  three  annulets  2, 6  and  4  in  number  respectively 42. 

42(43)     Body  small,  less  than  13  mm.  in  length;  Young-49 Pteronidea  sp.  11. 

43(42)     Body  large,  more  than  15  mm.  in  length;  on  Populus  balsamifera;  M-182;  G-pop. 

Pteronidea  sp.  12. 

44(41)     Colored  patches  on  first  three  annulets  2, 4,  and  4  in  number  respectively 45. 

45(46)    On  birch;  M-139 emcrita  MacGillivray. 

46(45)     On  Populus;  Y-45 lombardae  Marlatt. 

47(34)     Abdominal  segments  2-8  on  ventro-meson  with  black  spots 48. 

48(49)  Large  larvae,  20-23  mm.  in  length;  dorsum  without  dark  shade;  head  much  smaller 
than  thorax  in  width  and  height;  on  Salix;  Y-8.45(?)s-5-2.  .fulvicrus   Provancher. 

49(48)  Moderately  large  larvae,  less  than  20  mm.  in  length;  dorsum  always  with  dark  shade; 
head  comparatively  large,  only  slightly  smaller  than  thorax  in  width  and  height;  on 
Salix;M-119 evanida  MacGillivray. 

50(3)  Head  not  black  or  brown,  usually  greenish  with  few  linear  markings;  body  usually 
without  numerous  colored  patches 51. 

51(54)  Body  with  a  pair  of  distinct  fine  latero-dorsal  lines;  larvapods  with  1-2  setae  as 
viewed  from  side 52. 

52(53)  Head  with  a  black  line  extending  the  entire  length  of  epicranial  stem  to  the  occiput; 
on   Salix;  M-12 erudita  MacGillivray. 

53(52)  Head  without  black  line  extending  the  entire  length  of  epicranial  stem  to  the  occiput; 
on  Salix;  M-190 Pteronidea  sp.  13. 

54(51)  Body  without  a  pair  of  distinct  fine  dorso-lateral  lines;  larvapods  usually  with  3-5 
setae  as  viewed  from  side 55. 

55(58)     Head  entirely  green 58. 

56(57)     Suranal  process  sharply  pointed;  on  Rhododendron  canadense;  M-46 

Pteronidea  sp.  14. 

57(56)     Suranal  processes  bluntly  rounded;  on  Salix;  M-133 Pteronidea  sp.  15. 


88  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [406 

58(55)     Head  not  entirely  green,  usually  with  a  blackish  or  brownish  line  along  epicranial 

stem  and  one  dorsad  of  each  ocellara 59. 

59(64)    Suranal  process  sharply  pointed 60. 

60(61)    Body  tapering  caudad  uniformly  and  slightly;  uniformly  green;  on  Salix  cordala; 

Y-153-1-1,-153-? mendka  Walsh. 

61(60)     Body  not  tapering  caudad  uniformly  and  slightly;  abdomen  swollen  on  segments 

5-7;  body  not  uniformly  green 62. 

62(63)     Latus  of  each  segment  with  a  large  fuscous  patch;  tenth  abdominal  tergum  with 

caudal  margin  between  suranal  processes  straight;  on  Alnus;  M-71 

equina  MacGillivray. 
63(62)    Latus  of  each  segment  without  a  large  fuscous  patch;  tenth  abdominal  tergum  with 

caudal  margin  between  suranal  processes  convex;  on  birch;  M-61.  Pteronidea  sp.  16. 

64(59)     Suranal  processes  never  sharply  pointed  but  enlarged  at  distal  ends 65. 

65(66)     Antennae  with  segment  3  complete,  altho  reduced  to  a  mere  line  on  cephalic  aspect; 

on  birch;  M-60 Pteronidea  sp.  17. 

66(65)     Antennae  with  segment  3  incomplete;  Y-120  (on  Gleditsia  triacanthos);  Y-143-1 

on  Salix  cordata trilineata   Norton. 

Pontania  Costa 

Larvae  comparatively  small,  whitish  or  greenish,  usually  10-15  mm. 
in  length;  gall-makers  or  leaf-edge-rollers;  body  cylindrical,  thorax  usually 
not  swollen;  tenth  abdominal  tergum  usually  with  a  pair  of  suranal  pro- 
tuberances; when  the  paired  caudal  protuberances  are  normal  in  position, 
i.  e.,  near  the  lateral  ends  of  caudal  margin  of  the  segment,  the  tergum 
usually  with  paired  blackish  or  brownish  markings;  caudal  protuberances 
sometimes  very  minute  and  borne  on  the  caudal  margin  of  the  produced 
median  projection;  spiracles  winged  or  not  winged;  third  abdominal 
segment  with  four  annulets,  annulets  1-3  setiferous;  head  usually  dark 
brown  or  blackish  in  younger  specimens  and  yellowish  or  pale  brown  in 
older  specimens;  labrum  with  mesal  emargination  shallow  or  obsolete; 
maxillary  palpi  with  segment  2  longest,  usually  nearly  equal  in  length  to 
segments  3  and  4  taken  together;  antennae  with  four  segments,  segments 
fused  or  separate,  segments  1  and  2  usuallly  incomplete  and  separate, 
segment  3  sometimes  complete,  often  fused  with  segment  4;  larvapods 
setiferous,  with  four  or  more  setae. 

Most  Nematinae  with  gall-making  or  leaf-folding  larvae  belong  to  this 
genus.  The  different  types  of  galls  are  supposed  to  be  specific  and  are 
considered  of  systematic  value.  Many  species  are  indistinguishable  in  the 
immature  stages  except  by  the  morphology  of  the  galls  they  produce. 

SPECIES  OF  PONTANIA 
I.  Gall-Makers 
1(18)  Tenth  abdominal  tergum  with  or  without  the  paired  caudal  protuberances,  if  present, 
small,  blunt,  usually  not  longer  than  wide  at  proximal  end,  sometimes  borne  on 
caudal  projection  of  suranal  lobe;  tergum  without  paired  blackish  or  brownish 
markings;  ninth  abdominal  tergum  with  distinct  paired  markings  or  transverse  rows  of 
minute  spots 2. 


407]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  89 

2(3)  Tenth  abdominal  tergura  without  paired  caudal  protuberances;  tibia  distinctly 
longer  than  femur;  head  brownish  or  yellowish  with  space  between  ocellarae  across 
the  front  paler;  Y-8-4- 1,-8-4-3,-8-6-1,  C-y67,  M-212;  on  Salix pomum  Walsh. 

3(2)  Tenth  abdominal  tergum  with  paired  caudal  protuberances;  tibia  not  distinctly 
longer  than  femur 4. 

4(5)  Suranal  lobe  not  produced  caudad,  as  a  small  mesal  projection,  but  with  a  pair  of 
caudal  protuberances,  small  but  normal  in  position,  near  the  lateral  ends  of  the 
caudal  margin;  head  blackish  or  blackish  brown,  space  along  epicranial  suture  paler; 
spiracles  usually  not  winged;  dorsum  of  segments  not  transversely  marked  with 

gray;  on  Salix;  Y-7-1,-7-4-1,-8.8,  C-cu  201,  M-92 hyalina  Norton. 

5(4)  Suranal  lobe  produced  caudad,  forming  a  small  mesal  projection  which  bears  rudi- 
mentary paired  protuberances;  head  light  brown  with  front  and  vertex  dorsad  of 
each  ocellara  darker;  spiracles  usually  winged;  dorsum  of  segments  transversely 
marked  with  gray;  antennae  with  segments  3  and  4  fused;  labrum  with  mesal  emar- 

gination  obsolete 6. 

6(7)  Gall  not  transected  by  the  leaf,  but  attached  to  one  surface,  point  of  attachment 
showing  as  discolored  scar;  greater  part  of  gall  free  from  the  leaf;  two  or  more  galls 

sometimes  adjacent;  woolly  small-leaved  willows;  M-148 Pontania  sp.  1. 

7(6)       Gall  transecting  the  leaf;  usually  only  one  gall  on  a  leaf 8. 

8(9)       Gall  involving  the  midrib;  surface  of  gall  irregularly  constricted;  sometimes  2  or 

more  galls  adjacent;  M-226 devincta  MacGillivray. 

9(8)       Gall  not  involving  the  midrib  tho  extending  to  it 10. 

10(15)  Long  axis  of  gall  parallel  to  midrib;  leaf  transecting  the  gall  into  two  subequal 
parts 11. 

11(12)     Gall  kidney-shaped,  strongly  convex,  about  14  mm.  in  length;  M-213.  Pontania  sp.  2. 

12(11)     Gall  not  kidney-shaped 13. 

13(14)     Gall  bean-shaped,  slightly  convex;  12-14  mm.  in  length;  Y- 191-1-1 

demissa  McGillivray. 

14(13)     Gall  bean-shaped,  strongly  convex;  14-15  mm.  in  length;  M-262.  .Pontania  sp.  3. 

15(10)     Long  axis  of  gall  transverse  to  midrib 16. 

16(17)  Gall  transected  by  leaf  into  two  subequal  semiglobose  parts,  surface  not  constricted 
by  a  furrow;  M-211,-216 Pontania  sp.  4. 

17(16)  Gall  transected  by  leaf  into  two  unequal  parts;  surface  constricted  by  a  furrow; 
M-93 Pontania   sp.    5. 

2.     Leaf-folders 

18(1)  Tenth  abdominal  tergum  always  with  the  paired  caudal  protuberances 
which  are  sharply  pointed,  normal  in  position,  and  longer  than  wide  at  proximal 
end;  tergum  usually  with  paired  blackish  or  brownish  markings;  ninth  abdominal 
tergum  with  or  without  distinct  paired  markings  or  transverse  rows  of  minute 
spots 19. 

19(20)  Tenth  abdominal  tergum  without  distinct  paired  blackish  or  brownish  markings; 
head  entirely  yellowish;  M-150 Pontania  sp.  6. 

20(  1 9)    Tenth  abdominal  tergum  with  distinct  paired  blackish  or  brownish  markings 21. 

21(26)  Ninth  abdominal  tergum  without  any  markings  or  spots;  antennae  with  segment  3 
sometimes  incomplete 22. 

22(25)  Tenth  abdominal  tergum  with  markings  extending  entire  length  and  dumbbell- 
shaped  ;  antennae  with  segments  2  and  3  usually  complete 23. 

23(24)  Folded  portion  of  leaf  irregularly  wrinkled;  usually  both  edges  folded;  M-175. 
1-1 Pontania    sp.    7. 

24(23)  Folded  portion  of  leaf  not  irregularly  wrinkled;  usually  one  edge  folded;  Y-31-1-1, 
-8, 46(?)-2-2 Pontania  sp.  8. 


90  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [408 

25(22) 


26(21 

27(32 
28(29 

29(28 

30(31 

31(30 

32(27 
33(34; 

34(33 


35(36 


36(35 


37(42 
38(39 


39(38 
40(41 
41  (40 
42(37 


Tenth  abdominal  tergum  with  markings  not  extending  the  entire  length  and  not 
dumbbell-shaped;  antennae  with  segments  2  and  3  incomplete;  folded  portion  of  leaf 

irregularly  wrinkled;  often  both  edges  folded;  Y-139-1-1 Pontania  sp.  9. 

Ninth  abdominal  tergum  with  some  markings  or  spots;  antennae  with  segment  3 

usually  complete .  , 27. 

Ninth  abdominal  tergum  with  two  transverse  rows  of  minute  colored  spots 28. 

Tibia  longer  than  femur;  front  concolorous  with  vertex;  setae  on  abdominal  terga 

more  than  three  times  as  long  as  spiracles;  Y-166-1-1 Pontania  sp.10. 

Tibia  subequal  in  length  to  femur;  front  not  concolorous  with  vertex  but  darker;  setae 

on  abdominal  terga  less  than  three  times  as  long  as  spiracles 30. 

Head  blackish;  mature  larvae  9  mm.  in  length;  on  Salix;  Y-8.46(?)-l-2 

Pontania  sp.  11. 
Head  brownish;  mature  larvae  11  mm.  in  length;  on  Populus;  M-166 

Pontania  sp.  12. 
Ninth  abdominal  tergum  without  two  transverse  rows  of  minute  colored  spots ....  33. 
Ninth  abdominal  tergum  with  two  pairs  of  transverse  blackish  or  brownish  markings, 
interrupted  on  meson;  head  brownish  with  area  along  epicranial  suture  distinctly 

clear  and  paler;  Y-142-1 derosa  MacGillivray. 

Ninth  abdominal  tergum  with  one  pair  of  transverse  blackish  or  brownish  markings, 
interrupted  on  meson;  head  blackish  or  brownish  in  younger  specimens,  yellowish 
or  light  brown  in  older  specimens  with  area  along  epicranial  suture  not  distinctly 

paler 35. 

Tenth  abdominal  tergum  with  markings  not  reaching  the  paired  caudal  protuberances 
but  broken  on  caudal  half  into  minute  spots;  head  yellowish  with  two  minute  brown 
spots  on  front;  leaf-edge  folder,  folded  edges  not  irregularly  wrinkled;  M-146. 

Pontania  sp.  13. 
Tenth  abdominal  tergum  with  markings  reaching  the  paired  caudal  protuberances, 
not  broken  on  caudal  half  into  minute  spots;  yellowish  or  brownish  without  two 

minute  brown  spots  on  front 37. 

Ninth  abdominal  tergum  with  paired  markings  on  its  cephalic  half 38. 

Ninth  abdominal  tergum  with  a  transverse  row  of  minute  spots  caudad  of  paired 
markings;  leaf-edge-folder;  both  edges  often  folded  and  folded  portion  irregularly 

wrinkled;  M-145 Pontania  sp.  14. 

Ninth  abdominal  tergum  without  a  transverse  row  of  minute  spots  caudad  of  paired 

markings 40. 

Antennae  with  segment  3  incomplete;  only  one  edge  of  leaf-folded,  folded  portion  not 

irregularly  wrinkled;  M-89,-147 Pontania  sp.  15. 

Antennae  with  segment  3  complete;  both  edges  of  leaf  folded,  folded  portion  irregu- 
larly wrinkled;  M-116,-144 Pontania  sp.  16. 

Ninth  abdominal  tergum  with  paired  markings  on  caudal  half;  antennae  with 
segment  3  complete;  single  edge-folder,  folded  portion  not  irregularly  wrinkled; 
Y-8.46(?)-2-2  (in  part) Pontania  sp.  17. 


Nematid  genus  1. — Larvae  small,  greenish;  body  cylindrical,  tapering 
uniformly  toward  caudal  end;  segmentation  distinct;  annulation  indistinct; 
third  abdominal  segment  apparently  with  four  annulets,  annulets  1,  2,  and 
3  setiferous;  thoracic  legs  conspicuously  long,  nearly  as  long  as  thorax, 
slender,  with  trochanter  longer  than  femur;  larvapods  well  developed, 
setiferous;  tenth  abdominal  segment  without  the  paired  caudal  protuber- 
ances; head  circular,  front  flattened,  smaller  than  thorax  in  width  and 


409]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  91 

height;  antennae  with  four  segments,  segments  small,  incomplete,  with 
large  sensory  (?)  pits,  segments  sometimes  fused  in  part;  spiracles  not 
winged. 

This  genus  is  represented  by  a  single  unidentified  species  collected  by 
Chester  Young  on  Salix  at  Ithaca,  New  York.  The  larva  is  unique  in  the 
character  of  the  legs  in  that  the  trochanter  is  longer  than  the  femur. 
That  this  species  belongs  to  the  Nematinae  is  unquestionable  but  it  is  not 
closely  related  to  any  genus  in  particular  except  perhaps  to  Pontania. 
It  may  represent  an  undescribed  genus. 

Species  1. — Length,  10.5  mm.;  body  greenish;  head  brownish  with  dorsal 
half  of  front  dark  fuscous;  labrum  semicircular  with  slight  mesal  emar- 
gination;  maxillary  palpi  with  segment  1  nearly  as  long  as  segment  2 
which  is  cylindrical  and  as  wide  at  distal  end  as  at  proximal,  segment  3 
much  smaller,  segment  4  minute,  peg-like,  two  distal  segments  curved 
mesad;  galea  conical,  only  slightly  larger  than  labial  palpi;  thoracic  legs 
with  coxae  subequal  in  length  to  tibiae,  with  trochanter  slightly  shorter 
than  coxa,  and  as  long  on  dorsal  margin  as  on  ventral,  femur  shorter 
than  trochanter,  cylindrical,  three-fourths  as  wide  as  long,  tarsal  claws 
slightly  curved;  larvapods  with  1-2  setae  near  cephalic  aspect;  setae 
slender,  not  stiff,  rather  sparse;  tenth  abdominal  tergum  rounded  on 
caudal  margin,  with  few  setae;  subanal  lobe  with  several  setae;  abdominal 
segments  with  subspiracular  areas  with  two  setae  and  surpedal  areas  with  a 
single  setae;  on  Salix  nigra;  C-c.y.-77. 


Subfamily  Blennocampinae  "m 

Larvae  (Figs.  19-20)  moderately  large;  body  subcylindrical,  sometimes 
rather  robust,  tapering  uniformly  caudad,  venter  more  or  less  flattened, 
usually  distinctly  spinose;  segmentation  distinct;  annulation  indistinct; 
third  abdominal  segment  with  five  or  six  annulets,  rarely  apparently  with 
four;  thorax  sometimes  thickened;  thoracic  legs  well  developed,  normal, 
tibia  shorter  than  or  subequal  to  femur;  femur  produced  ventro-distad  as 
pointed  membranous  projection;  larvapods  on  segments  2-8  and  10,  normal 
in  form,  glabrous,  subsegmented,  distal  lobe  truncate  on  distal  margin 
and  often  curved  mesad;  tenth  abdominal  segment  usually  with  several 
spines  arranged  in  a  transverse  row  along  caudal  margin;  suranal  and  sub- 
anal  lobes  with  several  setae;  head  small,  sparsely  setiferous,  narrower  than 
thorax,  front  slightly  convex;  antennae  with  five  segments,  slender,  elon- 
gately  conical;  ventral  glands  wanting;  glandubae  sometimes  present; 
spiracles  rarely  winged;  spines  often  very  long,  furcate,  with  two,  three,  or 
five  branches,  barbed,  or  represented  by  conical  tubercles  or  sometimes 
reduced  to  short  bifurcate  tubercles;  cuticle  microscopically  and  densely 
spinulate;  ultimate  stage  occurs,  in  which  all  setae  and  spines  are  lost  and 


92  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [410 

body  becomes  colorless  and  glabrous;  free  leaf -feeders;  sometimes  gregari- 
ous. 

The  Blennocampinae  as  restricted  by  MacGillivray  is  a  large  sub- 
family rich  in  genera  and  species,  and  is  related  to  Fenusinae  and  Scolion- 
eurinae.  This  is  in  agreement  with  Konow's  statement  altho  this  author 
makes  his  tribe  Blennocampides  the  third  in  his  subfamily  Tenthredinini. 
Rohwer  would  group  the  majority  of  the  genera  under  consideration  in 
his  subfamily  Empriinae,  but  take  out  the  genera  Phymatocera  and  Tomos- 
tethus  from  the  subfamily  and  place  them  in  a  subfamily  by  themselves. 
This  arrangement  has  an  advantage  in  classifying  the  larvae  because  of 
the  fact  that  the  larvae  of  Tomostethus  lack  the  characteristic  spines  which 
readily  distinguish  the  Blennocampinae  from  all  other  groups  in  the  larval 
stages.  The  following  key  will  separate  the  genera  examined,  with  two  addi- 
tional ones,  Erythraspides  and  Periclista,  whose  diagnostic  characters 
are  taken  from  Dyar's  paper  (1898b). 

GENERA  OF  BLENNOCAMPINAE 

1(2)  Body  without  spines;  with  six  annulets,  annulets  2  and  4  each  with  a  transverse 
row  of  minute  but  stalked  glandubae Tomostetltus  Konow. 

2(1)      Body  with  spines 3. 

3(10)  Third  abdominal  segment  with  six  distinct  annulets;  spines  usually  unbranched  but 
conical  if  branched,  very  short  and  minute,  tenth  abdominal  tergum  with  small 
conical  unbranched  spines 4. 

4(7)      Body  spines  conical  and  not  bifurcate,  blackish 5. 

5(6)      Spiracles  with  distinct  black  wings M onopkadnus  Hartig. 

6(5)      Spiracles  without  distinct  black  wings Hypergyricus  MacGillivray 

7(4)      Body-spines  not  conical  but  bifurcate,  blackish  or  whitish 8. 

8(9)      Spines  whitish;  tenth  abdominal  tergum  not  marked Blennocampa  Hartig. 

9(8)  Spines  black;  tenth  abdominal  tergum  marked  with  black.  .Erythraspides  Ashmead. 
10(3)      Third  abdominal  segment  with  five  annulets,  rarely  apparently  with  four;  spines  in 

part  usually  bifurcate,  long,  never  short  and  conical 11. 

11(12)  Tenth  abdominal  tergum  with  a  mesal  spine  cephalad  of  caudal  marginal  row  of 
spines;  subdorsal  spines  of  prothorax  with  five  branches;  prothoracic  spinal  formula: 
5-2-1:5:1-2;  third  abdominal  segment:2-2-2K):3-2-2:2-l:l-2;  ultimate  tergum  1-1-1: 

2:2 Monophadnoides  Ashmead. 

12(11)    Tenth  abdominal  tergum  without  a  mesal  spine  cephalad  of  caudal  marginal  row  of 

spines;  subdorsal  spines  of  prothorax  with  three  branches  at  most 13. 

13(14)  Second  annulet  of  third  abdominal  segment  with  three  spines  dorsad  of  spiracular 
line;  host-plants  not  confined  to  Quercus  species;  prothoracic  spinal  formula:  2-2-2: 

2-3:1-2;  third  abdominal  segment  2-2-2:1:2-2-2:2-1:1:1 Isodictium  Ashmead. 

14(13)  Second  annulet  of  third  abdominal  segment  with  two  spines  dorsad  of  spiracular 
line;  host-plants  confined  to  species  of  Quercus;  otherwise  resembling  the  preceding 
genus Periclista  Konow. 

Tomostethus  Konow 
Larvae  moderately  large,  length  17-21  mm.,  rather  robust,  yellow- 
ish white;  body  subcylindrical,  tapering  little  caudad,  venter  flattened, 


411]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  93 

without  spines,  sparsely  and  microscopically  setiferous;  head  black,  shiny, 
much  smaller  than  thorax;  third  abdominal  segment  with  six  annulets, 
annulets  2  and  4  each  with  a  transverse  row  of  few  stalked  glandubae; 
tenth  abdominal  segment  without  spines,  truncate  on  caudal  margin; 
spiracles  not  winged,  but  with  a  pair  of  faint  ventral  crescentic  brown 
marks;  antennae,  (5,  4,  3),  2,  1  in  older  larvae  and  5,  (4,  3),  2,  1  in  younger 
larvae;  maxillary  palpi,  4,  2, 1,  3,  pointed;  labial  palpi  rather  slender,  (1,  2); 
ultimate  stage  entirely  whitish. 

Tomosthethus  bardus  Say. — Length,  18  mm.;  width  of  head,  1.9  mm.; 
body  whitish  with  yellowish  tinge,  in  older  specimens  yellowish  white; 
head  shiny  black  with  clypeus  alone  lighter  in  color;  legs  blackish  brown; 
larvae  gregarious;  on  ash;  G-2,  Y-8.14. 

Tomostethus  multicinctus  Rohwer. — According  to  Sasscer's  description 
(1911)  the  larvae  of  this  species  are  indistinguishable  from  the  preceding 
species  but  the  bred  adults  have  been  assigned  to  this  species  by  Rohwer. 
Larvae  have  not  been  examined. 

Blennocampa  Hartig 

Larvae  rather  small,  length  15-20  mm.;  greenish;  body  subcylin- 
drical,  slender,  tapering  uniformly  caudad;  spines  small,  bifurcate,  tubercle- 
like or  conical;  head  very  small,  third  abdominal  segment  with  six  an- 
nulets, annulets  2  and  4  spinose;  tenth  abdominal  segment  spinose,  spines 
conical,  unbranched,  numerous,  arranged  in  four  rows,  1:  1:  1-1-1: 
1-1-1-1-1;  typical  prothoracic  spinal  formula:  2-2-1-1-1: 1-1-1: 1: 1-1; 
third  abdominal  segment,  2-2-1: 1:2-2-1: 1-1-1: 1-1-1;  antennae,  5,  (1,  2,  3, 
4);  maxillaray  palpi,  (2,  3,  4),  1,  slender,  pointed;  labial  palpi  (1,  2), 
nearly  equal  to  two  distal  segments  of  maxillary  palpi  taken  together; 
legs  with  femur  longer  than  tibia;  larvapods  normal  in  form,  more  or 
less  rounded  at  distal  end. 

Blennocampa  spiraeae  Dyar. — Length,  16.5  mm.;  width  of  head,  1.2 
mm.;  body  greenish;  head  pale  brown;  legs  concolorous  with  body;  ocel- 
larae  entirely  black,  tips  of  mandibles  and  tarsal  claws  brown;  maxillary 
palpi  with  segment  4  and  labial  palpi  with  segment  2  deep  brown;  pro- 
thoracic  formula  of  spines  variable,  2-2-1-1-1  or  2-3-1-1,  or  2-1-1-1;  ab- 
dominal segment  on  surpedal  lobe  with  from  2-1  to  2-2  spines;  tenth 
abdominal  tergum  with  small,  short,  conical  spines  arranged  in  four  rows 
as  follows:  (1)  two  pair  of  spines  on  each  side  of  meson,  (2)  two  spines  on 
each  side  of  the  meson,  near  the  center  of  the  tergum,  (3)  lateral  pairs 
sometimes  with  additional  spines,  and  (4)  the  last  and  caudal  row  of 
five  spines  on  each  side  of  meson  along  the  caudal  margin  of  tergum,  the 
three  lateral  spines  closer  together  than  the  others;  on  Spiraea;  not  bred: 
M-28. 


94  ILLINOIS  BIOLOGICAL  MONOGRAPHS  1412 

Erythraspides  Ashmead 

Larvae  comparatively  speaking  small,  inconspicuously  spinose, 
greenish;  third  abdominal  segment  with  five  annulets,  annulets  2  and  4 
each  with  three  minute  bifurcate  spines. 

According  to  Dyar's  Key  (1898)  the  larvae  of  Erythraspides  pygmaeae 
is  distinguished  from  those  of  Blennocampa  spiraeae  by  the  black  head 
and  spines  of  the  former.  Record  is  meager,  and  without  specimens  no 
adequate  diagnosis  can  be  given. 

MONOPHADNUS  HaRTIG 

Larvae  rather  small,  length  less  than  15  mm.,  spotted;  body  rather 
robust,  only  slightly  and  uniformly  tapering  caudad;  tubercles  conical, 
small,  blackish,  not  furcate;  third  abdominal  segments  with  six  annulets, 
annulets  2  and  4  tuberculate;  tenth  abdominal  tergum  with  two  rows  of 
tubercles,  some  of  which  are  bifurcate;  pro  thoracic  spinal  formula: 
1-1:1:1:1;  third  abdominal  segment,  1-1-1:1:1-1-1:1:1;  antennae  5,  (4,  3, 
2),  1;  maxillary  palpi  (4,  2),  1,  3;  labial  palpi  (1,  2);  palpi  rather  thick  and 
conical;  spiracles  with  distinct  black  wings. 

Monophadnus  nubilipennis  Norton. — Length,  14  mm.;  width  of  head, 
1.3  mm.;  head  blackish  brown,  clypeus  alone  lighter;  body  dirty  white 
with  yellowish  tinge;  legs  grayish;  on  hellebore;  Y-42,-8.42. 

Hypergyricus  MacGillivray 
Larvae  rather  large  and  robust,  spotted;  length  16-20  mm.,  body 
subcylindrical,  tapering  but  slightly  and  uniformly  caudad;  tubercu- 
late, tubercles  conical,  short,  stout,  usually  not  furcate;  third  abdominal 
segment  with  six  annulets,  annulets  2  and  4  tuberculate;  tenth  abdominal 
segment  with  two  rows  of  few  tubercles;  prothoracic  spinal  formula 
variable,  but  with  a  single  tubercle  on  supraspiracular  area  and  two  tubercles 
ventrad  of  it;  third  abdominal  segment  also  with  variable  number  of 
tubercles,  only  two  on  subspiracular  area;  tubercles  not  furcate;  spiracles 
with  faint  ventral  crescentic  brown  marks  but  without  definite  wings; 
antennae  rather  obtusely  rounded,  segments  decreasing  in  diameter  from 
proximal  to  distal,  but  increasing  in  length;  suranal  and  subanal  lobes 
strongly  convex,  with  numerous  short  recumbent  setae;  legs  with  femur 
distinctly  longer  than  tibia;  distal  portion  of  femur  dilated  and  produced 
vehtro-mesad. 

SPECIES  OF  HYPERGYRICUS 
Head  black,  genae,  antennariae,  ventral  half  of  front  and  clypeus  lighter  in  color;  tubercles 
blackish;  body  whitish,  faint  grayish  shade  and  yellowish  tinge  in  older  stages; 
legs  grayish  brown;  antennae  with  segment  3  and  4  subequal  in  length;  prothorax 
with  spines,  2-2:1:1:1;  third  abdominal  segment,  1-1:0:1-1:1:1;  latus  of  body  along 
supraspiracular  lines  with  broken  band  of  grayish  shade,  marks  distinct  and  square 


413]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  95 

dorsad  of  each  spiracle;  on  leaves  and  fruits  of  Smilacina  racemosa;  length,  18  mm.; 

width  of  head,  1.8  mm.;  Y-73,-29-10,-8.73,  M-181 fumipennis  Norton. 

Head  brownish  yellow;  length,  17  mm.;  width  of  head,  1.9  mm.;  spots  on  dorsum  variable; 
body  whitish  with  faint  yellowish  tinge;  legs  concolorous  with  body;  supraspiracular 
lines  without  smoky-black  band;  prothoracic  spines  1-1-1  or  1-1-1-1:1:1:1  or  3;  third 
abdominal  segment  with  1-1 ;  1:1-1-1 :1 :1 ;  any  of  the  dorsal  tubercles  may  be  wanting; 
otherwise  similar  to  the  preceding  species;  Y;  20  specimens  collected  by  Mr.  J.  R. 
Malloch  on  Smilacina  in  Illinois Hypergyricus  sp.  1. 

MONOPHADNOIDES  ASHMEAD 

Larvae  small,  distinctly  spinose,  greenish;  length  less  than  17  mm.; 
body  subcylindrical,  tapering  caudad,  rather  slender;  spines  furcate, 
with  two,  three,  or  more  branches;  third  abdominal  segment  with  five, 
apparently  four,  annulets,  annulets  2  and  3  spinose;  prothorax  with  spines, 
5-2-l:(5  or  3):1:2;  third  abdominal  segment,  2-2-2:0:(3  or  2)-2-2:2-l:l-2; 
tenth  abdominal  tergum  with  a  mesal  furcate  spine  cephalad  of  caudal 
marginal  row  of  spines;  legs  rather  slender,  femur  slightly  longer  than 
tibia,  not  dilated  at  distal  end;  spiracles  unwinged;  maxillary  palpi, 
(1,  4),  (2,  3);  labial  palpi,  (1,  2);  maxillary  and  labial  palpi  slender,  pointed; 
antennae,  5,  (1,  2,  3,  4),  sharply  pointed  and  slender;  semigregarious. 

Monophadnoides  rubi  Harris. — Length,  16  mm.;  width  of  head,  1.6  mm.; 
head  pale  brownish  green,  distinctly  setiferous,  spines  whitish,  branches 
sometimes  light  brown;  length  of  longer  branches  subequal  to  the  width 
of  head  as  seen  in  profile;  tenth  abdominal  tergum  with  mesal  spines  with 
2-3  branches,  on  the  caudal  third  of  the  tergum  cephalad  of  the  marginal 
row  of  spines,  sometimes  another  smaller  unbranched  spine  cephalad  of 
the  furcate  mesal  spines;  marginal  row  of  spines,  beginning  with  mesal 
spine,  consists  of  two  simple,  one  bifurcate  and  lower,  and  lateral  simple 
spine  on  each  side  of  meson;  on  Rubus  and  also  on  giant  Ragweed;  Y-8.17, 
M-19,-183,  G-562,  500-3. 

ISODYCTITJM  ASHMEAD 

Larvae  rather  small,  usually  distinctly  spinose;  length  less  than  17  mm.; 
body  subcylindrical,  tapering  caudad,  rather  slender;  third  abdominal 
segment  with  five  annulets,  annulets  2  and  4  spinose,  sometimes  appar- 
ently four-annulate,  with  annulets  2  and  3  spinose;  spines  furcate,  usually 
with  two  to  three  branches,  branches  usually  conspicuously  long,  some- 
times small,  short,  but  always  sharply  pointed  at  distal  end;  spiracles  never 
winged;  thoracic  legs  normal,  femur  subequal  in  length  to  or  longer  than 
tibia;  head  blackish  or  spotted  on  vertex  and  front  or  uniformly  greenish; 
spines  on  prothorax,  2-2-2-1:2-2:1:2;  on  third  abdominal  segment  2-2-2:1: 
2-2-1:1:1;  tenth  abdominal  segment  with  a  marginal  row  of  spines,  usually 
four  on  each  side  of  meson. 


96  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [414 

Several  species  have  been  examined.  None  of  the  material  has  been 
identified  altho  the  following  larva  may  belong  to  /.  subgregarium. 

Isodyctium  sp.  1. — Length,  15.5  mm.;  head,  1.5  mm.  wide;  head  marked 
on  vertex  and  front  with  large  confluent  brownish  spots,  those  on  front 
sometimes  separate;  body  uniformly  greenish;  legs  concolorous  with 
body,  femur  subequal  in  length  to  tibia;  spines  blackish,  very  long  and 
furcate,  with  large  proximal  end,  those  ventrad  of  spiracular  lines  whitish; 
those  one-half  as  long  as  head  are  wide  as  seen  in  profile;  prothorax  with 
spines,  2-2-2-1:2-2:1:2;  third  abdominal  segment,  2-2-2:1:2-2-2:2-1:1-1; 
tenth  abdominal  tergum,  2-1:2:2,  the  mesal  pair  sometimes  with  confluent 
bases;  maxillary  palpi,  (4,  2),  3, 1 ;  labial  palpi,  1,2;  ultimate  stage:  entirely 
whitish,  vertex  pale  brown,  third  abdominal  segment  with  five  distinct 
annulets,  setiferous  but  not  spinose;  on  oak;  M-6. 

Subfamily  Fenusinae 

Larvae  (Fig.  21)  very  small;  body  semicylindrical,  venter  flattened, 
depressed,  tapering  caudad,  glabrous;  segmentation  distinct;  annulation 
indistinct;  third  abdominal  segment  with  either  one  or  apparently  2-4 
annulets;  thorax  slightly  swollen,  prothorax  sometimes  with  dorsal  and 
ventral  shields;  legs  small,  short,  apparently  with  four  segments,  spreading 
cephalo-laterad;  larvapods  on  abdominal  segments  2-8,  vestigial,  merely 
mound-like;  anal  larvapods  obsolete;  tenth  abdominal  tergum  glabrous 
without  suranal  processes  or  caudal  protuberances,  sometimes  with  small 
mesal  projections;  suranal  and  subanal  lobes  glabrous;  head  sparsely 
setiferous,  depressed,  subtriangular  in  outline,  wedge-shaped  in  profile 
narrower  than  thorax  and  overlapped  on  caudal  third  by  prothorax;  ver- 
tical furrows  wanting;  antennae  apparently  with  single  segment;  antacoria 
large;  ocellarae  minute,  located  dorso-caudad  of  antennariae;  ventral 
glands  wanting;  glandubae  wanting;  spiracles  indistinctly  winged;  cuticle 
sometimes  with  microscopic  but  distinct  chitinized  dentiform  spines; 
larvae,  leaf-miners. 

The  Fenusinae  is  a  small  subfamily  represented  by  four  genera  in  the 
Nearctic  region.  Systematists  have  always  considered  this  group  as 
closely  related  to  the  Scolioneurinae  and  Blennocampinae.  MacGillivray 
is  the  only  one  who  would  assign  them  subfamily  rank.  Konow  listed  three 
European  species,  dohrni,  nlmi,  and  pumila,  under  the  old  generic  name 
Kaliosysphinga.  The  first  two  are  now  considered  as  types  of  distinct 
genera.  They  have  been  introduced  into  this  country  and  are  liable  to  do 
considerable  damage  at  times.   The  genera  studied  are  separable  as  follows: 

GENERA  OF  FENUSINAE 

Caudal  end  of  body  rounded,  without  a  mesal  suranal  protuberance;  sternum  of  ninth  abdom- 
inal segment  with  a  pair  of  swellings  covered  with  distinct  microscopic  dentiform  spines: 


415]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  97 

tenth  sternum  strongly  convex,  much  shorter  than  ninth  sternum 

Kaliofenusa  MacGillivray. 

Caudal  end  of  body  truncate,  with  a  mesal  suranal  protuberance;  sternum  of  ninth  abdominal 

segment  flattened,  uniformly  and  microscopically  spinulate;  tenth  sternum  slightly 

convex,  nearly  as  long  as  the  ninth  sternum Fenusa  Leach. 

Kaliofenusa  MacGillivray 

Larvae  very  small,  greenish  white;  length  less  than  12  mm.;  thorax 
broadest  on  meso thorax;  declivous  on  dorsum  from  metathorax  toward 
the  head;  head  only  slightly  depressed,  front  convex;  mouth-parts  normal 
except  labium,  which  is  flattened;  mandibles  rather  thick  in  profile; 
dorsum  and  venter  covered  with  brownish,  irregular,  microscopic  dentiform 
spines,  larger  on  the  center  of  segment  and  larvapods;  caudal  end  of  body 
rounded;  tenth  abdominal  tergum  without  mesal  protuberance;  sternum 
of  ninth  segment  with  a  pair  of  microscopically  dentate  swellings;  tenth 
sternum  strongly  convex,  much  shorter  than  ninth  sternum. 

Kaliofenusa  ulmi  Sundevall. — Length,  10  mm.;  width  of  head,  .9  mm.; 
head  light  brown,  legs  brown,  ocularia,  mandibles,  maxillary  palpi,  deep 
brown;  sternum  of  ultimate  segment  with  transverse  depression  on  the 
caudal  third  distinct;  leaf -miners,  on  Ulmus,  feeding  on  all  tissues  except 
upper  and  lower  epidermis;  Y-4-1, -4-2,-8.4. 

Fenusa  Leach 

Larvae  very  small,  length  less  than  12  mm.,  greenish  white;  body  rather 
uniform  in  width  except  at  caudal  end  which  tapers  suddenly  and  dis- 
tinctly; head  strongly  depressed;  front  flattened;  mouth-parts  protruding 
beyond  the  distal  end  of  mandibles;  body  uniformly  and  microscopically 
spinulate;  no  distinct  localized  microscopic  dentiform  spines;  caudal 
end  of  body  truncate;  tenth  abdominal  tergum  with  a  distinct  mesal  coni- 
cal suranal  protuberance;  sternum  of  ninth  segment  rather  flattened, 
without  microscopically  dentate  swellings;  tenth  sternum  slightly  convex, 
nearly  as  long  as  ninth. 

Fenusa  dohrni  Tischbein. — Length,  10-11  mm.,  width  of  head,  1.1  mm.; 
head  brown;  prothorax  with  dorsal  and  ventral  shields  indicated;  thoracic 
legs  light  brown,  trochanter  wanting,  femur  subequal  in  length  to  tibia; 
tibia  with  proximal  end  subequal  in  diameter  to  distal  end  of  femur; 
tenth  abdominal  sternum  with  transverse  depression  in  caudal  fourth 
indistinct;  body  often  greenish,  green  adipose  tissues  being  visible  thru 
the  cuticle;  dorsal  vessel  showing  thru  as  light-colored  line;  leaf -miners  on 
Alnus  vulgaris,  feeding  habit  similar  to  that  of  Kaliofenusa  ulmi;  Y-4.  A, 
-43-1-2. 


98  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (416 

Subfamily  Scolioneurinae 

Larvae  (Fig.  22)  very  small;  body  semicylindrical,  somewhat  de- 
pressed, flattened  on  venter,  broader  on  thorax,  tapering  caudad,  glabrous, 
greenish,  never  with  bright  patterns;  segmentation  distinct;  annulation 
indistinct,  third  abdominal  segment  with  two  annulets;  larvapods  rudi- 
mentary, mere  swellings  on  abdominal  segments  2-7,  the  anal  pair  adjacent 
on  meson,  forming  a  single  protuberance;  thorax  thickened,  prothorax 
often  with  distinct  dorsal  and  ventral  chitinized  shields;  thoracic  legs 
small,  slender,  distinctly  five-segmented,  directed  laterad;  head  depressed, 
sub  triangular,  wedge-shaped  in  profile,  narrower  than  thorax;  mouth- 
parts  flattened  and  protruding,  labium  large,  with  submentum  and  mentum 
strongly  chitinized;  antenna  one-segmented;  vertical  furrows  usually 
wanting;  tenth  abdominal  tergum  abbreviated,  glabrous;  spiracles  usually 
winged;  glandubae  obsolete;  ventral  glands  wanting;  cuticle  often  with 
minute  dentiform  tubercles;  leaf-miners. 

The  Scolioneurinae  is  a  small  subfamily  containing  six  genera,  four  of 
which  are  peculiar  to  the  Nearctic  region.  All  six  genera  are  represented 
in  the  North  American  fauna.  Prior  to  the  recognition  of  the  subfamily 
by  MacGillivray,  the  species  belonging  to  it  were  referred  to  the  genera 
Fenusa  and  Blennocampa.  Konow  first  segregated  a  species  of  Entodecta 
and  later  more  of  Scolioneura  from  Blennocampa,  placing  them,  together 
with  Fenusa  and  its  allies,  in  other  genera  of  his  tribe  Blennocampides. 
Rohwer  would  separate  the  genera  of  the  Scolioneurinae  from  those  of 
the  Blennocampinae  but  unite  them  with  those  of  the  Fenusinae  in  the 
tribe  Messini  of  his  subfamily  Messinae.  The  close  affinity  of  the  Fenu- 
sinae and  Scolioneurinae  is  evident  from  the  fact  that  all  known  larvae 
of  these  subfamilies  are  leaf-miners  and  that  they  possess  similar  types  of 
structural  modifications.  The  definitions  here  given  are  based  on  obser- 
vations on  two  American  species  of  Metallus  supplemented  by  writings  of 
European  students — Cameron,  Brischke,  and  Zaddach. 

Metallus  Forbes 

Larvae  small,  length  10-13  mm.,  whitish  or  pale  brownish;  body  de- 
pressed, rather  stout,  mesothorax  broadest;  pleuron  of  each  segment 
tuberculate;  cuticle  with  microscopic  irregular  chitinized  dentiform 
tubercles,  those  on  center  of  dorsum  and  venter  largest;  head  directed 
ventro-cephalad,  much  narrower  than  thorax,  attached  to  the  ventral 
part  of  prothorax;  vertical  furrows  wanting;  front  twice  as  long  as  wide, 
labrum  subtriangu'ar,  small;  antennae  mamma-like;  ocellarae  incon- 
spicuous, about  one-fifth  the  diameter  of  the  antennaria;  mouth-parts 
small  but  distinct,  slightly  modified;  mandibular  dentes  sharp;  maxillary 
palpi  three-segmented,  stipes  elongate,  galea  digit-like,  slightly  curved 


417]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  99 

mesad  and  subequal  in  size  to  palpi,  lacinia  thin,  small,  plate-like;  labium 
comparatively  large,  flattened;  labial  palpi  inconspicuous,  apparently 
2-segmented;  ligula  globose  and  proturding;  thoracic  legs  with  coxa  large, 
stump-like,  following  segments  suddenly  smaller  and  slender,  trochanter 
ring-like,  femur  as  long  as  wide,  tibia  longer  than  femur,  cylindrical, 
chitinized,  tapering  gradually  to  distal  end,  tarsal  claws  broadly  curved, 
sharp;  mesothorax  and  metathorax  with  a  dorsal  membranous  swelling 
on  each  side  of  the  meson;  spiracles  distinctly  and  semicircularly  winged; 
tenth  abdominal  tergum  small,  convex;  anal  setae  wanting;  subanal  lobe 
small,  prominently  convex. 

SPECIES  OF  METALLUS 

Head  brownish,  not  concolorous  with  body,  epicranial  suture  very  distinct;  dorsal  and  ventral 
shields  distinct  and  brown;  dorsal  shield  transverse,  covering  dorsum  of  prothorax, 
proventral  shield  very  large,  occupying  entire  venter  between  prothoracic  legs  caudad  of 
and  continuous  with  brown  cervacoria,  mesoventral  and  metaventral  shields  small, 
transverse,  triangular  between  legs;  labium  with  submentum  strongly  chitinized,  brown 
with  dark  carina  on  meson  and  along  caudal  margin,  mentum  brown,  longer  than  wide; 
larvapods  with  crescentric  brownish  band  on  cephalic  aspect;  length,  11-12  mm.;  on 
Rubus;  Y rubi  Forbes. 

Head  pale  or  whitish,  concolorous  with  body,  at  least  not  distinctly  colored ;  dorsal  and 
ventral  shields  obsolete,  only  rarely  faintly  indicated;  labium  with  submentum  broad 
and  without  dark  median  longitudinal  carina,  depression  on  meson  rarely  present, 
never  dark  and  distinct;  larvapods  without  crescentric  brownish  band  on  the  cephalic 
aspect;  length,  10  mm.;  on  Rubus;  Y bethunei  MacGillivray. 

The  larvae  of  Metallus  rubi  were  described  by  Forbes,  but  the  original 
specimens  are  apparently  lost.  The  description  given  here  is  based  on 
specimens  in  the  Cornell  Collection.  Forty-three  larvae  of  M.  bethunei 
were  examined  thru  the  courtesy  of  Mr.  H.  G.  Crawford  of  Guelph, 
Ontario,  Canada. 

Subfamily  Hylotominae 
Larvae  (Fig.  23)  moderately  large;  body  semicylindrical,  venter 
flattened,  distinctly  wider  than  high,  widest  on  abdominal  segments  1-3, 
tapering  caudad,  caudal  segments  only  one  half  the  width  of  widest  seg- 
ments; yellowish  green,  spotted  or  not;  segmentation  distinct;  third 
abdominal  segment  with  three  annulets,  all  setiferous,  often  tuberculate; 
thoracic  legs  large,  spreading  laterad,  apparently  six-segmented  inclusive 
of  claws;  claws  sharply  curved,  large,  distinctly  separated  from  fifth 
segment  by  suture  and  with  a  large  pulvillus-like  swelling;  larvapods 
setiferous,  on  abdominal  segments  2-6  and  with  rudimentary  7th  pair,  or  on 
2-7  and  10  with  rudimentary  8th  pair;  antennae  one-segmented,  either 
conical  or  button-like,  if  conical,  larvapods  on  abdominal  segments  2-6 
and  10;  spiracles  distinctly  winged;  glandubae  obsolete;  tenth  abdominal 
tergum  without  suranal  processes. 


100  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [418 

The  Hylotominae  in  the  adult  stage  is  closely  allied  to  the  Schizocerinae. 
but  in  the  larval  stages  their  affinities,  if  extant,  are  not  so  manifest, 
The  laravae  are  peculiar  in  possessing  six-segmented  -thoracic  legs  and 
varying  numbers  of  larvapods.  The  shape  and  general  appearance  of  the 
larvae  are  so  characteristic  that  they  alone  are  sufficiently  reliable  for 
identification  in  the  field.  Two  genera  are  represented  in  the  Nearctic 
region,  the  genus  Atomacera,  which  includes  only  a  few  species,  has  not 
been  studied. 

Hylotoma  Latreille 

Head,  conspicuously  shiny  black,  brown  or  yellowish,  or  with  a  brown 
median  streak;  body  with  minute  blackish  tuberculate  setiferous  spots 
forming  interrupted  longitudinal  rows  along  some  or  all  of  the  subdor- 
sal, latero-dorsal,  supraspiracular,  subspiracular,  and  pedal  lines;  annu- 
lation  usually  2,  3,  1;  annulet  1  with  a  few  minute  setae,  annulets  2  and 
3  with  a  transverse  row  of  a  few  stiff  brown  setae  together  with  very 
minute  setae  scattered  around  the  larger  setae;  subspiracular  tubercles 
obsolete;  pedal  area  prominent,  produced  laterad  and  oblique,  extending 
entire  length  of  segment;  maxillary  palpi  normal,  four-segmented,  segment 
1  flattened,  with  distinct  mesal  projection,  segments  2  and  3  cylindrical, 
segment  4  minute,  peg-like;  labial  palpi  normal,  three-segmented;  larva- 
pods  located  close  together  near  the  meson,  proximal  portion  chitinized,  seti- 
ferous, distal  portion  small,  membranous,  non-setiferous,  bluntly  rounded, 
those  on  seventh  or  eighth  abdominal  segment  lacking  membranous 
distal  portion. 

The  genus  is  divisible  into  two  sections  by  the  structure  of  antennae  and 
number  of  larvapods.  Owing  to  the  incompleteness  of  published  records 
of  larvae  of  this  genus,  involving  in  some  cases  confusion  in  specific  identi- 
fication, it  is  not  possible  to  determine  many  of  the  specimens  collected. 
The  following  key  will  separate  the  species  represented  in  the  collections 
studied. 

SPECIES  OF  HYLOTOMA 

1  (10)  Antennae  distinctly  conical  or  peg-like,  twice  as  long  as  wide;  larvapods  on  abdominal 
segments  2-6  and  10,  seventh  segment  with  rudimentary  pair;  head  always  uniformly 
blackish,  brownish,  or  yellowish;  body  always  with  numerous  minute  blackish  spots 
arranged  longitudinally  along  subdorsal,  dorso-lateral,  supraspiracular  and  pedal 
lines f 2. 

2(5)  Head  always  black,  thoracic  legs  with  all  segments  blackish;  tenth  abdominal  tergum 
blackish 3. 

3(4)  Tenth  abdominal  segment  on  ventral  half  blackish;  area  between  larvapods  with 
minute  colored  spots;  area  ventrad  of  pedal  folds  with  minute  spots;  latus  of  each 
segment  with  a  few  very  minute  secondary  setiferous  spots  besides  regular  tubercu- 
late spots;  on  Crataegus  Y-194-3   194-2;  on  Prunus?   Y- 194-5 Hylotoma  sp.  1. 

4(3)  Tenth  abdominal  segment  on  ventral  half  unmarked,  whitish;  area  between  larvapods 
without  minute  colored  spots;  area  ventrad  of  pedal  folds  without  minute  spots; 


419]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  101 

latus  of  each  segment  without  minute  setiferous  spots;  on  Alnus:  Y- 194-4 

Hylolonia  sp.  2. 

5(2)      Head  not  always  blackish  but  usually  yellowish  or  brown;  thoracic  legs  not  with  all 

segments  blackish,  segments  distad  of  coxa  usually  brownish  or  brownish  yellow; 

tenth  abdominal  tergum  not  always  blackish 6. 

6(7)  Head  blackish;  tenth  abdominal  tergum  yellowish;  subanal  lobe  yellowish;  spots 
between  larvapods  numerous  and  brownish;  latus  of  each  segment  with  many  very 
minute  secondary  setiferous  spots;  tuberculate  spots  of  body  yellowish  with  brown 

border;  on  oak;  Y-214-1-2 Hylotoma  sp.  3. 

7(6)      Head  yellowish  or  reddish  brown;  tenth  abdominal  tergum  blackish;  subanal  lobe 

whitish 8. 

8(9)  Area  ventrad  of  pedal  folds  with  many  minute  setiferous  spots;  area  between  larva- 
pods  sometimes  with  spots;  spots  on  body  not  uniformly  blackish  or  brownish  but 
blackish  on  cephalic  and  also  usually  on  caudal  portion  of  the  body  those  on  middle 
portion  brownish  or  yellowish  with  brown  border  sometimes  spots  all  pale  yellowish 

brown;  head  reddish  or  yellowish  brown;  on  Crataegus;  Y-222 

scapularis  Klug. 

9(8)      Area  ventrad  of  pedal  fold  without  spots;  area  between  larvapods  never  with  spots; 

spots  on  body  uniformly  blackish  or  brownish;  head  yellowish  or  yellowish  brown; 

on  elm;  C-C.U.  668    Y-29-24 Hylotoma  sp.  4. 

10(1)  Antennae  button-like,  usually  wider  than  long;  larvapods  on  abdominal  segments 
2-7  and  10,  eighth  segment  with  rudimentary  pair;  head  blackish  brownish  or  with  a 
distinct  median  streak  from  occiput  to  front;  body  sometimes  not  spotted  except 
on  each  side  of  the  meson  on  cephalic  segments 11. 

11(14)  Head  blackish  or  brownish;  body  distinctly  and  regularly  spotted;  tenth  abdominal 
tergum  and  subanal  lobe  usually  blackish;  thoracic  legs  usually  with  coxae  blackish 
or  brownish  and  other  segments  brownish  or  grayish 12. 

12(13)  Tenth  abdominal  tergum  and  subanal  lobe  whitish;  all  colored  areas  or  spots  of  body 
brownish;  area  between  larvapods  with  few  setiferous  spots;  area  ventrad  of  pedal 
fold  with  many  setiferous  spots;  on  Salix  discolor;  C-Young  61. . .  .Hylotoma  sp.  5. 

13(12)  Tenth  abdominal  tergum  and  subanal  lobe  blackish  or  brownish;  all  colored  areas 
or  spots  blackish  or  brownish;  area  between  larvapods  usually  without  setiferous 
spots;  area  ventrad  of  pedal  fold  with  varying  number  of  spots;  on  Prunus;  Y-1946-1 
G-Onekama  No.  23;  Maine  1915;  C-C.U.  656  C.U.  sub.  64 Hylotoma  sp.  6. 

14(11)  Head  yellowish  or  light  brownish  with  brown  streak  along  epicranial  stem;  body  not 
regularly  and  distinctly  spotted  except  along  dorso-meson  on  cephalic  segments; 
tenth  abdominal  tergum  never  blackish  or  brownish;  thoracic  legs  always  con- 
colorous  with  body;  Y-185-1-2  (Azalea)  Y-185  (Willow)  M-113  (birch  bred)  M-108 
(hazel) macleayi     Leach. 

Subfamily  Schizocerinae 

Larvae  (Fig.  24)  small;  body  subcylindrical,  flattened  on  venter, 
tapering  caudad,  mesothoracic  and  metathoracic  segments  somewhat 
swollen,  prothorax  distinctly  tapering  cephalad;  whitish  or  creamy  white, 
never  spotted  or  striped;  segmentation  and  annulation  indistinct;  third 
abdominal  segment  with  three  annulets,  all  annulets  provided  with  a 
transverse  row  of  tubercles;  spiracles  on  annulet  1;  tenth  abdominal 
tergum  without  suranal  or  caudal  protuberances;  larvapods  on  abdominal 
segments  2-8  and  10,  the  venter  of  ninth  segment  with  a  pair  of  minute 


102  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (420 

protuberances;  thoracic  legs  modified,  pro  thoracic  legs  apparently  four- 
segmented,  distal  segment  pad-like,  tarsal  claws  wanting;  mesothoracic 
and  metathoracic  legs  apparently  three-segmented,  distal  segment  pad- 
like with  a  sharp  claw  on  cephalic  side;  antennae  apparently  one-segmented, 
segment  large  with  several  clear  spots;  antennaria  ventrad  or  slightly 
caudad  of  ocularium;  spiracles  winged;  glandubae  obsolete;  in  younger 
specimens  larvapods  sometimes  very  indistinct;  tubercles  often  indistinct; 
leaf-miners. 

The  Schizocerinae  is  represented  in  the  Nearctic  region  by  a  single 
genus,  Schizocerus,  and  includes  a  limited  number  of  species.  Modern 
systematists  have  always  associated  this  subfamily  with  the  Hylotominae, 
the  two  being  separated  by  the  presence  or  absence  of  the  free  part  of 
Scj  in  the  front  wing.  The  larvae  of  this  subfamily  are  unique  in  having 
thoracic  legs  and  maxillary  and  labial  palpi  modified  by  reduction  in  the 
number  of  segments. 

Schizocerus  Lepeletier 

Larvae  small,  length  less  than  15  mm.,  creamy- whitish;  head  small, 
pale  brown,  higher  than  wide,  sparsely  and  microscopically  setiferous; 
annuJation  1,  2,  3;  annulets  above  spiracular  b'nes  with  tubercles,  2  on 
annulet  1,  four  on  annulet  2,  and  three  on  annulet  3,  annulet  1  with  a  row 
of  tubercles  on  venter;  a  row  of  tubercles  between  larvapods  and  surpedal 
area;  subspiracular  area  not  tuberculate  or  warty;  tenth  abdominal 
tergum  small,  only  slightly  convex,  tubercules  almost  obsolete,  with 
several  stiff  short  setae  on  caudal  margin;  venter  of  ultimate  segment 
with  distinct  anal  larvapods,  subanal  lobe  with  a  pair  of  long  and  short 
tubercles  on  each  latero-caudal  margin;  maxillary  palpi  apparently  three- 
segmented,  distal  segment  very  minute,  formula,  2,  1,  3;  labial  palpi 
apparently  two-segmented;  mandibles  as  viewed  from  side  narrow  and 
slender;  totaglossa  of  labium  large;  spiracles  winged,  wings  small,  oblong; 
spiracular  line  dividing  the  latus  into  two  subequal  dorso-ventral  parts. 

Schizocerus  zabriskiei  Ashmead. — Head  pale  brownish-green,  body 
whitish;  in  younger  specimens  head  brownish,  body  with  minute  tubercles 
touched  with  brown;  legs,  and  venter  between  legs  brownish;  tubercles 
ventrad  of  surpedal  area  and  dorsad  of  larvapods  usually  three  in  number 
in  mature  larvae  and  two  in  younger  larvae;  mature  specimen,  length, 
13  mm.;  width  of  head,  1.3  mm.;  on  Portulaca;  Y,  G. 

Schizocerus  sp.  1. — Larvae  indistinguishable  from  the  preceding  species. 
This  species  was  collected  at  Muncie,  HI.,  by  Dr.  Edna  Mosher,  who 
bred  adults.    It  is  considered  by  Dr.  MacGillivray  to  be  a  new  species. 


421]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  103 

Subfamily  Acordulecerinae 

Body  (Fig.  25)  subcylindrical,  tapering  caudad,  venter  flattened, 
thorax  distinctly  swollen;  segmentation  distinct;  annulation  indistinct, 
third  abdominal  segment  with  apparently  three  annulets,  all  annulets 
tuberculate,  setiferous;  thoracic  legs  5-segmented,  spreading  laterad,  distal 
segment  consisting  of  a  sharp  recurved  claw  and  caudal  membranous 
globose  swelling;  pro  thoracic  legs  one-half  as  large  as  meta  thoracic; 
larvapods  rudimentary  on  abdominal  segments  2-7  and  10,  increasing  in 
size  from  cephalic  pair  to  sixth  pair;  tenth  abdominal  segment  truncate, 
small,  without  suranal  processes;  antennae  flattened,  apparently  1-seg- 
mented;  abdominal  segments  2-4  or  2-5  and  8  with  crescentic  sucker-like 
protuberances,  one  on  each  postsubspiracular  protuberance;  ventral 
glands  wanting;  spiracles  not  winged;  glandubae  wanting. 

The  Acordulecerinae,  according  to  MacGillivray  (1906),  is  represented 
on  the  North  American  continent  by  a  single  genus,  Acordulecera.  Rohwer 
would  divide  the  subfamily  into  two  tribes,  Acordulecerini  and  Conocoxini, 
the  former  including  besides  Acordulecera,  Pantherix  and  possibly 
Thulea  and  the  latter  Conocoxa  and  Nithulea.  A  radically  different 
arrangement  is  that  of  Konow  who  regarded  Acordulecera  as  one  of 
fourteen  genera  included  in  his  tribe  Lobocerotides  which  was  one  of  four 
tribes  constituting  his  subfamily  Lophyrini.  Konow  seems  to  have  been 
unfamiliar  with  the  larvae  of  the  Nearctic  genus  Acordulecera,  for  he 
speaks  of  the  larvae  of  Lophyrini  as  "mit  16  Abdominalbeinen ;  an  Coni- 
feren." — a  characterization  not  at  all  applicable  to  the  genus  under 
consideration.  The  host-plant  of  two  species  of  Acordulecera  have  been 
recorded,  and  one  species  recognized  in  the  larval  stage.  I  have  examined 
larvae  of  several  unbred  species. 

Acordulecera  Say 
Larvae  very  small,  length  less  than  12  mm.,  greenish,  never  spotted  or 
striped;  head  usually  brownish  or  pale;  annulation,  3,  (2,  1);  prothorax 
constricted;  annulets  with  transverse  row  of  slight  tubercles,  each  bearing 
slender  peg-like  setae;  lateral  lobes  distinct;  tenth  abdominal  tergum  with 
several  setae;  suranal  and  subanal  lobes  with  several  setae;  maxillary  palpi 
rather  slender,  uniformly  tapering  distad;  mandible  thick;  labial  palpi 
small;  ligula  dilated,  rounded;  free  leaf-feeders;  gregarious. 

SPECIES  OF  ACORDULECERA 

1(4)       Sucker-like  protuberances  on  abdominal  segments  2-5  and  8 2. 

2(3)  Head  with  vertex  blackish  brown,  front  distinctly  lighter  in  color;  legs  whitish 
concolorous  with  body;  sucker-like  protuberances  with  three  marginal  setae;  length 
9.5  mm.;  width  of  head   1.2  mm.;  on  butternut;  Y-8.93(?)-2-2. .  .Acordulecera  sp.  1. 

3(2)  Head  with  vertex  light  brown,  epicranial  stem  deep  brown,  front  sometimes  deep 
brown;  in  young  specimens  head  entirely  dark  brown;  legs  brown;  sucker-like 


104  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [422 

protuberances  with  three  marginal  setae;  length   11  mm.;  width  of  head   1.3  mm.; 

on  chestnut  and  butternut;  Y-93  C-cu  667 Acordulecera  sp.  2. 

4(1)      Sucker-like  protuberances  on  abdominal  segments  2-4  and  8 5. 

5(8)      Sucker-like  protuberances  with  three  marginal  setae;  on  oak 6. 

6(7)      Head  light  brown  with  epicranial  stem  deep  brown  or  brownish  with  vertical  furrows 

lighter  in  color;  legs  brownish;  length  9  mm.;  width  of  head    1.2  mm.;  Y-131  -137, 

C-cu  680,  M-37 Acordulecera  sp.  3. 

7(6)      Head  yellowish  or  light  brown,  with  epicranial  stem  concolorous  with  body;  length, 

7  mm.;  width  of  head,  1.1  mm.;  M-239,  M-243,  C-yll dorsalis  Say. 

8(5)      Sucker-like  protuberances  with  five  marginal  setae;  head  deep    brown,    vertical 

furrows  and  epicranial  arms  lighter  in  color;  legs  whitish,  concolorous  with  body; 

length,  9  mm.;  width  of  head,  1.2  mm.;  on  hickory;  Y-144-5 tnusta  MacGillivray. 

Family  Pamphiliidae 

Larvae  (Fig.  1)  of  medium  size;  body  subcylindrical,  slightly  flattened 
on  the  ventral  aspect;  sublateral  lobe  on  the  ventro-lateral  margin  dis- 
tinct, moderately  large;  body  slender  to  robust;  segmentation  and  annula- 
tion  distinct;  cuticle  microscopically  setiferous,  appearing  smooth,  often 
delicate,  transparent;  color  usually  greenish  or  creamy  white;  head  semi- 
globose,  prominent,  as  wide  as  thorax;  color  creamy  or  brownish  or  blackish; 
mouth  directed  ventrad;  head  completely  exposed,  sparsely  setiferous; 
epicranial  suture  and  vertical  furrows  present;  antennae  extremely  long, 
setaceous,  conspicuous,  seven-segmented;  ocularia  located  ventro-laterad 
of  antennariae;  mouth-parts  normal,  sericos  produced  and  prominent; 
prothorax  with  shield-like,  usually  brownish,  broad  patches  on  the  dorsal 
and  lateral  aspects;  thoracic  legs  modified,  setiform,  sharply  pointed, 
segments  cylindrical,  distal  segment  very  long,  slender,  straight;  third 
abdominal  segment  with  four  annulets  on  dorsal  and  ventral  aspects; 
spiracles  on  the  second  annulet;  larvapods  wanting;  eighth  abdominal 
segment  on  the  venter  mesad  of  the  lateral  lobe  with  a  fleshy  protuber- 
ance resembling  a  larvapod,  ninth  segment  cylindrical,  smaller  than  the 
preceding;  tenth  segment  depressed,  rounded  on  the  caudal  margin, 
usually  setiferous,  sometimes  conspicuously  so,  often  with  colored  patches, 
always  with  a  median  hook-like  suranal  process  near  the  caudal  margin 
of  the  tergum;  subanal  lobe  with  a  pair  of  setiform,  three-segmented 
conspicuous  subanal  appendages;  insects  one-  or  two-brooded;  spinning 
silken  web  or  rolling  leaves  for  their  nests;  solitary  or  gregarious;  pupate  in 
the  ground. 

The  Pamphiliidae  is  an  easily  circumscribed  family  of  eight  or  nine 
genera  and  a  large  number  of  species  which  are  peculiar  to  the  Northern 
hemisphere.  The  adults  differ  from  all  other  Hymennoptera  except  the 
Xyelidae  in  the  preservation  of  the  subcostal  vein  in  the  hind  wings. 
In  this  character  it  is  more  generalized  than  the  Xyelidae  altho  it  is 
more  specialized  than  this  family  in  other  features  of  venation.    Brischke 


423]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  105 

and  Zaddach  (1865)  discussed  the  immature  stages  and  biology  of  eleven 
European  species  of  the  Pamphiliidae  and  pointed  out  that  certain  of 
their  habits  may  be  of  taxonomic  significance.  The  larvae  of  these  species 
fall  into  one  or  the  other  of  two  groups  according  to  the  type  of  nests  they 
build.  The  first  group  contains  those  whose  larvae  build  nests  by  tying  the 
leaves  of  their  food-plants  together  with  threads  of  silk  and  are  either 
solitary,  as  Lyda,  or  gregarious,  as  Cephaleia  and  Neurotoma.  The 
second  group  consists  of  those  whose  larvae  build  nests  by  rolling  the 
edge  of  the  leaves  of  their  food-plants  and  live  inside  the  tubes  so  formed, 
as  Pamphilius.  Some  of  this  latter  group  make  portable  nests  out  of 
detached  pieces  of  leaves,  as  Pamphilius  inanitus  on  Rosa.  The  adults, 
however,  are  so  closely  related  to  each  other  that  Rohwer  (1911)  con- 
sidered such  a  subdivision  impractical.  Konow  (1901),  in  his  analytical 
table  of  the  larvae,  included  sixteen  species,  representing  four  genera,  but 
did  not  register  any  Nearctic  species.  According  to  this  writer  (1905)  the 
larvae  of  Lyda  and  Cephaleia  feed  on  coniferous  plants  while  those  of 
Neurotoma  and  Pamphilius  attack  deciduous  plants.  Nothing  is  known 
concerning  the  biology  of  Anoplolyda.  Dyar  (1895)  included  in  his  table 
ten  Nearctic  pamphilids  but,  excepting  Pamphilius  ocreatus,  all  were  uni- 
dentified and  many  were  taken  from  descriptions  given  by  Packard  (1890). 

Of  about  fifty-five  Nearctic  species  representing  seven  genera,  Acan- 
tholyda,  Itycorsia,  Cephaleia,  Caenolyda,  Neurotoma,  Pamphilius,  and 
Anoplolyda,  only  five  species  have  been  identified  in  the  larval  stage, 
and  the  food-plants  of  about  six  species  recorded. 

Four  identified  and  several  unidentified  species  have  been  examined. 
It  is  not  possible  to  define  the  genera  with  this  limited  material;  the 
species  studied  can  be  separated  as  follows. 

SPECIES  OF  PAMPHILIIDAE 

1(14)  Subanal  appendages  with  the  second  segment  longer  than  or  subequal  to  the  third 
segment,  never  distinctly  shorter;  head  usually  dark-colored ;  tenth  abdominal  tergum 
with  colored  patches 2. 

2(3)  Subanal  appendages  with  the  second  segment  subequal  in  length  to  the  third,  all 
segments  black;  first  segment  longer  than  the  two  distal  segments  taken  together; 
head  black;  body  olive-green  with  yellowish  lateral  lobes;  on  spruce;  Packard 
(1890)-35 Pamphiliid  sp.  1. 

3(2)  Subanal  appendages  with  the  second  segment  longer  than  third,  the  third  usually 
darker  in  color  than  the  others;  first  segment  longer  than  or  nearly  equal  to  the  two 
distal  segments  taken  together;  head  dark  brown  to  green 4. 

4(5)  Head  green;  tenth  abdominal  tergum  without  colored  patches;  body  green;  subanal 
appendages  with  the  second  and  third  segments  black;  on  Pinus  strobus;  Packard-83. 

Pamphiliid  sp.  2. 

5(4)  Head  not  green,  usually  brownish;  tenth  abdominal  tergum  with  or  without  colored 
patches;  body  not  greenish,  sometimes  reddish  or  olivaceous;  subanal  appendages 
usually  with  segments  brownish;  on  Pinus  and  Abies 6. 


106  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [424 

6(13)    Head  brown  to  yellowish 7. 

7(12)    Head  dark  brown 8. 

8(9)  Head  paler  along  epicranial  arms;  subanal  appendages  with  first  segment  as  long  as 
all  the  other  segments  taken  together;  all  segments  pale  to  light  brown;  length,25  mm. ; 
width  of  head,  3  mm.;  body  robust,  large;  following  parts  dark  brown:  head  except 
along  epicranial  arms,  prothoracic  shields,  thoracic  surpedal  lobe,  coxae,  sterna 
between  thoracic  legs,  cervical  sclerites,  markings  on  the  tenth  abdominal  segment, 
median  suranal  process,  and  antenae;  ocellarae  black;  suranal  process  short  and 
erect;  tenth  abdominal  tergum  with  a  pair  of  lateral  patches,  not  connected  along 
caudal  margin;  tenth  abdominal  sternum  with  a  median  brown  patch,  distinctly 
rounded  on  cephalic  margin;  subanal  appendages  light  brown,  first  segment  equal 
in  length  to  other  two  taken  together,  segment  2  longer  than  3;  thoracic  legs  with 
fifth  segment  as  long  as  fourth,  and  third  taken  together;  antennal  formula:  (2,  5), 
3,  6,  1,  (4,  7);  cuticle  distinctly  reticulate,  each  area  brownish;  three  specimens  in 
MacGillivray  collection  bearing  label  "Cephalaeia  sp.  No.  839?  Maine."  (The 
identification  is  open  to  question,  but,  since  these  larvae  are  readily  distinguished 
from  the  larvae  of  Pamphilius  and  Neurotoma  by  the  characters  used  in  the  table 
here,  they  may  be  considered,  tentatively  at  least,  as  representing  the  genus  Cephal- 

eia.) Cefhalcia    sp.    1. 

9(8)      Head  not  paler  along  epicranial  arms,  but  uniformly  brownish 10. 

10(11)     Head  pitch-brown;  body  pinkish  to  reddish  brown;  on  spruce;  Packard-36 

Pamphiliid  sp.  3. 

11(10)  Head  horny  brown;  body  horny  brown;  subanal  appendages  with  first  segment 
longer  than  other  two  taken  together,  third  segment  brown;  on  Pinus  strobus; 
Packard-84 Pamphiliid  sp.  4. 

12(7)  Head  yellowish  to  brownish  yellow;  body  pale  brick-red  or  yellowish,  each  segment 
with  a  large  reddish  spot  on  the  spiracular  line;  subanal  appendages  with  first  segment 
nearly  equal  in  length  to  other  two  taken  together;  all  segments  blackish;  on  Pinus 
strobus;  Packard-85 Pamphiliid  sp.  5. 

13(6)  Head  pale  red,  with  a  black  spot  on  the  front;  body  reddish  olive-green  with  purplish 
meso-dorsal  line;  on  Austrian  pine;  closely  related  to  Lyda  campestris;  Packard-82. 

Pamphiliid  sp.  6. 

14(1)  Subanal  appendages  with  the  second  segment  distinctly  shorter  than  the  third;  head 
variously  colored,  blackish  to  pale;  tenth  abdominal  tergum  either  with  or  without 
colored  patches IS. 

15(18)  Tenth  abdominal  tergum  with  a  colored  patch  on  each  side,  median  triangular  patch 
between  the  cephalic  ends  of  the  lateral  patches  wanting;  lateral  patches  connected 
along  the  caudal  margin  of  tergum;  sternum  with  a  large  colord  patch 16. 

16(17)  Head  blackish  or  dark  brownish,  in  younger  specimens  pale  brown;  subanal  append- 
ages with  first  segment  longer  than  other  two  segments  taken  together,  third  longer 
than  second,  all  segments  brown,  the  third  darker;  cervical  sclerites  pale  brown, 
dorsal  and  lateral  shields  of  pro  thorax  pale  to  light  brown,  patches  on  the  ultimate 
segment  brownish;  body  with  a  pink  dorsal  line  on  the  meson;  antennae  in  mature 
specimens  with  formula,  (2, 3,  5),  1,  7,  (4,  6) ;  ocularium  about  one-third  the  diameter 
of  antennaria;  ocellarae  small,  eccentric,  near  the  mesal  margin  of  ocularium; 
mouth-parts  brownish;  length,  19  mm.;  width  of  head,  1.9  mm.;  on  wild  cherry; 
G Neurotoma  fasciata    Norton. 

17(16)  Head  lighter  in  color,  yellowish,  sometimes  brownish  yellow;  subanal  appendages  with 
first  segment  nearly  equal  to  other  two  taken  together,  all  segments  black;  following 
parts  blackish:  prothoracic  shields,  thoracic  legs,  markings  on  ultimate  segment, 
subanal  appendages,  ocularia,  thoracic  sterna;  the  black  markings  of  tenth  abdominal 


425)  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  107 

tergum  connected  along  the  caudal  margin;  black  marking  of  tenth  sternum  large, 
completely  covering  the  sternum,  and  with  its  cephalic  margin  between  the  subanal 
appendages  straight;  antennae  with  formula,  (3,  5),  2,  1,  7,  (6,  4);  length,  18  mm.; 
width  of  head,  1.7  mm.;  on  plum;  G NeurolomainconspicuaNorton. 

18(15)  Tenth  abdominal  tergum  either  with  a  colored  patch  on  each  side  and  with  a  median 
triangular  patch  between  the  cephalic  ends  of  the  lateral  patches  always  present,  the 
lateral  patches  sometimes  not  connected  along  the  caudal  margin  of  the  tergum, 
the  sternum  with  a  large  colored  patch;  or  the  tergum  without  colored  patches  and 
the  sternum  either  with  a  pair  of  small  round  spots  or  without  markings 19. 

19(22)  Tenth  abdominal  tergum  with  two  lateral  triangular  patches  and  one  mesal  patch 
and  sternum  with  a  large  colored  patch 20. 

20(21)  Head  blackish;  body  greenish-white;  subanal  appendages  with  the  first  segment  longer 
than  the  other  two  taken  together,  all  segments  pale  brown,  the  third  sometimes 
darker;  following  parts  blackish:  head  uniformly,  antennae,  prothoracic  shields, 
thoracic  lateral  lobe,  markings  on  ultimate  segment,  suranal  hook,  cervical  sclerites, 
and  coxae;  antennae  with  formula,  (3,  2),  5,  1,  7,  (4,  6);  eighth  uromere  with  a  pair 
of  marginal  ventral  glands  near  caudal  portion  of  the  sublateral  lobe,  both  pale 
brown;  in  life,  body  glossy  white  with  diffused  fleshy-reddish  tint;  antennae  and 
subanal  appendages  whitish;  length,  19  mm.;  width  of  head,  1.9  mm.;  on  Cornus; 
nests  made  by  rolling  edges  of  leaves  cut  across  from  the  margin  to  the  midrib; 
gregarious;  Y-125 Pamphilius  sp.  1. 

21(20)  Head  light  brown,  with  a  black  spot  on  the  apex  of  front;  subanal  appendages  with 
the  first  segment  nearly  equal  in  length  to  the  other  two  taken  together,  two  proximal 
segments  creamy,  third  deep  brown;  body  whitish  green;  ocularia  brown,  a  black  spot 
at  the  origin  of  the  epicranial  arms;  following  parts  brown:  thoracic  shields,  cervical 
sclerites,  and  markings  on  the  ultimate  segment;  tenth  abdominal  tergum  with  a 
median  cephalic  triangular  patch  between  the  lateral  patches;  subanal  appendages 
with  second  segment  longer  than  half  the  length  of  the  third;  thoracic  legs  pale  or 
creamy;  antennae,  beyond  the  first  segment,  deep  brown,  with  formula:  (2,  3,  5), 

1,  7,  (4,  6);  length,  19  mm.;  width  of  head,  1.8  mm.;  on  blackberry;  G 

Pamphilius  dentatus  MacG. 

22(19)     Tenth  abdominal  tergum  without  colored  patches 23. 

23(26)    Tenth  abdominal  sternum  without  a  pair  of  small  colored  patches 24. 

24(25)  Head  uniformly  pale  brown;  subanal  appendages  with  the  first  segment  as  long  as 
other  two  taken  together,  the  second  shorter  than  the  third,  all  segments  pale  brown; 
ocularia  large,  about  one-third  the  diameter  of  antenaria,  black;  following  parts 
blackish  brown:  narrow  prothoracic  shields,  cervical  sclerites,  and  antennae;  suranal 
hook  brown  without  colored  base;  antennae  with  formula,  (2,  3),  5,  1,  7,  (4,  6); 
length,  12  mm.;  width  of  head,  1.5  mm.;  host  unknown;  Y-163-3.  (This  species 
closely  resembles  P.  persicus  MacG.) Pamphilius  sp.  2. 

25(24)  Head  not  uniformly  pale  brown,  vertex  brown,  front  with  a  brown  spot;  subanal 
appendages  with  the  first  segment  as  long  as  the  other  two  taken  together,  distal 
two  segments  brownish;  following  parts  brown:  prothoracic  shields,  cervical  sclerites, 
antennae,  and  suranal  process;  legs  pale  brown,  darker  in  young  specimens;  length, 
17  mm.;  width  of  head,  1.8  mm.;  on  blackberry;  M-69 Pamphilius  sp.  3. 

26(20)  Tenth  abdominal  sternum  with  a  pair  of  small  colored  patches;  head  pale  to  light 
brown,  front  sometimes  with  a  brown  spot,  usually  without  it;  subanal  appendages 
with  the  first  segment  nearly  equal  in  length  to  other  two  taken  together,  the  second 
segment  shorter  than  the  third,  all  segments  pale  to  brownish;  ocularia  and  mandible 
at  distal  end  blackish  brown;  suranal  process  brown  with  its  base  pale;  antennae 


108  ILLINOIS  BIOLOGICAL  MONOGRAPHS  {426 

brown;  tenth  abdominal  sternum  with  small  brown  round  spot  on  each  side;  length, 
16  mm.;  width  of  head,  1.6  mm.;  larvae  solitary,  leaf-edge  rollers  on  Cornus;  M. 

Pamphilius  ocreaius  Say. 

Family  Cephidae 

Body  (Fig.  2)  cylindrical,  sometimes  slightly  depressed,  enlarged  at 
thorax,  slightly  arid  uniformly  tapering  caudad,  slender  or  moderately 
stout;  segmentation  usually  distinct;  annulation  sometimes  indistinct; 
cuticle  smooth  or  verrucose,  microscopically  and  very  sparsely  setiferous; 
color  generallly  pale  or  creamy  white,  never  with  distinct  bright  marks; 
head  circular  in  contour,  semiglobose,  moderately  large,  narrower  than 
thorax,  caudal  portion  concealed  by  prothorax,  pale  brown  or  concolorous 
with  body,  sparsely  setiferous;  mouth-parts  directed  ventrad,  normal 
in  form,  brownish;  antennae  with  four  or  five  segments,  conical;  oceliarae 
small,  with  ocularia  less  than  one-fifth  the  diameter  of  antennaria  and 
located  latero-caudad  of  it;  epicranial  suture  and  vertical  furrows  present; 
mesothorax  distinctly,  and  metathorax  with  dorsal  and  lateral  aspects 
somewhat  swollen;  thoracic  legs  vestigial,  fleshy,  mamma-like,  tarsal 
claws  wanting;  third  abdominal  segment  with  two  or  three  annulets, 
sometimes  indistinct;  venter  with  three  annulets;  larvapods  wanting, 
sometimes  with  slight  swellings  in  normal  position  of  larvapods;  lateral 
lobes  prominent,  extending  the  entire  length  of  the  segment;  tergum  of 
ultimate  segment  with  mesal  longitudinal  broad  depression  and  distinct 
suranal  process;  sternum  of  ultimate  segment  with  a  pair  of  inconspicuous 
vestigial,  papilliform  subanal  appendages  ventrad  of  the  cephalic  end  of 
the  anal  slit;  internal  feeders,  boring  into  the  stem  of  monocotyledonous 
and  herbaceous  plants  and  bushes;  pupation  in  tunnels  in  the  host-plants. 

The  Cephidae  contains  about  fourteen  genera  and  is  moderately  rich 
in  number  of  species,  some  of  them  of  intercontinental  distribution. 
Nine  genera  are  represented  in  North  America.  Practically  all  systematists 
have  considered  this  group  as  a  distinct  aggregate  worthy  of  family  rank. 
Rohwer  (1911),  however,  has  expressed  the  opinion  that  future  studies 
may  possibly  make  it  advisable  to  unite  this  group  with  the  Xyelidae 
and  to  treat  each  of  them  as  subfamilies.  There  have  so  far  been  no  facts 
or  reasons  brought  to  light  which  call  for  such  a  step.  On  the  other  hand, 
MacGillivray's  study  has  emphasized  the  fact  that  "so  far  as  the  wings 
are  concerned,  they  (Cephidae)  are  the  most  distinct  of  any  group  of  the 
Tenthredinoidea,  and  are  only  indirectly  related  to  any  of  the  other 
families."  They  are  generalized  in  the  manner  of  the  origin  of  media 
but  are  specialized  in  other  features  of  the  wings.  On  the  basis  of  larval 
characters  this  family  is  related  to  the  Pamphiliidae  and  is  quite  unrelated 
to  the  Xyelidae. 

The  systematic  position  of  the  osculant  genus  Syntexis  is  unsettled. 
In  the  original  description  Rohwer  (1915)   stated  that  this  genus  has 


427]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  109 

affinities  with  both  the  Cephidae  and  Xiphydriidae  and  on  the  basis  of 
venation,  it  probably  belongs  to  the  latter  as  denned  by  MacGillivray. 
Certain  features  other  than  venation,  however,  led  Rohwer  to  place  it  in 
the  Cephidae.  It  is  not  safe  to  venture  any  opinion  without  careful 
examination  of  the  larvae,  but  their  antennae  and  their  lack  of  papilliform 
subanal  appendages  suggest  close  affinity  with  the  Xiphydriidae. 

At  least  six  out  of  sixteen  American  species  have  been  recognized 
in  the  larval  stages  and  their  host-plants  recorded.  Janus  integer  and 
Cephus  cinctus  are  economic  pests.  Konow's  tribe  Macrocephides  includes 
the  species  whose  larvae  bore  into  the  pith  of  shrubs  and  woody  twigs, 
and  his  tribe  Cephides  embraces  those  whose  larvae  bore  into  the  stalks 
of  Graminaceae. 

Middleton  (1917)  published  descriptions  and  keys  for  distinguishing  the 
larvae  of  five  species  representing  four  genera,  Adirus,  Janus,  Cephus,  and 
Hartigia  together  with  a  definition  of  the  groups  based  on  "characters 
common  to  all  the  genera  studied  and  probably  to  the  family."  He 
reserved  for  future  discussion  the  question  of  the  systematic  position  of 
the  Cephidae,  but  pointed  out  the  obvious  affinity  of  this  group  with  the 
Siricidae  on  one  hand  and  the  Pamphiliidae  on  the  other.  Gahan  (1920) 
described  the  larva  of  Tracheitis  tabidus  (Fab.)  and  added  a  key  for  sepa- 
rating this  larva  from  that  of  Cephus  cinctus  and  C.  pygmaeus. 

GENERA  OF  CEPHIDAE 

1(10)     Papilliform  subanal  appendages  present  on  the  ultimate  abdominal  segment 2. 

2(3)  Suranal  process  depressed  on  the  distal  portion,  oval  in  cross-section,  with  strongly 
chitinized  dentiform  tubercles  on  the  proximal  portion;  antennae  five-segmented. 

Janus  Stephens. 

3(2)  Suranal  process  not  depressed  on  the  distal  portion,  circular  in  cross-section,  with  or 
without  strongly  chitinized  dentiform  tubercles  on  the  proximal  portion;  antennae 
four-segmented 4. 

4(5)  Suranal  process  proximad  of  distal  cylindrical  portion  with  strongly  chitinized 
dentiform  tubercles Adirus  Konow. 

5(4)  Suranal  process  proximad  of  distal  cylindrical  portion  without  strongly  chitinized 
dentiform   tubercles 6. 

6(7)  Terga  of  eighth  and  ninth  abdominal  segments  setiferous,  each  with  a  transverse  row 
of  distinct  setae;  tenth  abdominal  tergum  as  viewed  from  side  strongly  convex  and 
truncate  on  the  caudal  aspect;  suranal  process  with  stiff  setae  not  arising  from  distinct 
chitinized  bases Trachelus  Jurine. 

7(6)  Terga  of  eighth  and  ninth  abdominal  segments  glabrous,  each  without  a  transverse 
row  of  distinct  setae;  tenth  abdominal  tergum  as  viewed  from  side  not  strongly 
convex  and  not  truncate  on  the  caudal  aspect  but  gradually  declivous  caudad; 
suranal  process  with  stiff  setae  arising  from  distinct  chitinized  bases 8. 

8(9)  Suranal  process  with  distal  chitinized  portion  very  short  and  ring-like,  or  very 
long  and  cylinder-like,  more  than  twice  as  long  as  wide;  suranal  process  with  a 
single  transverse  row  of  setae  proximad  of  the  distal  chitinized  portion  or  with  two  or 
more  whorls  of  setae;  the  distal  margin  of  the  distal  chitinized  portion  not  distinctly 
serrate Cephus  Latreille. 


110  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [428 

9(8)      Suranal  process  with  distal  chitinized  portion,  as  long  as  wide,  cylinder-like;  suranal 
process  proximad  of  the  distal  chitinized  portion  with  two  or  more  whorls  of  setae; 

distal  margin  of  the  distal  chitinized  portion  minutely  but  distinctly  serrate 

Hartigia  Schiodte. 
10(1)      PapQliform  subanal  appendages  on  the  ultimate  abdominal  segment  wanting. 

Syntexis  Rohwer. 

Should  Cephus  and  Hartigia  (Middleton,  1917)  and  Tracheitis  (Gahan, 
1920)  prove  to  possess  five-segmented  antennae,  as  reported,  contrary  to 
the  observations  of  the  present  writer,  the  genus  Janus  can  be  separated 
from  them  by  the  chitinized  dentiform  tubercles  and  Trachelus  by  the 
glabrous  eighth  and  ninth  abdominal  terga. 

Jantjs  Stephens 
Antennae  distinctly  with  five  segments;  segments  1  and  2  short, 
ring-like,  segment  3  longer,  but  half  as  wide  as  segment  1,  segment  4 
cylindrical,  longer  than  wide,  segment  5  elongate-conical,  twice  as  long  as 
wide,  subequal  in  length  to  or  shorter  than  segment  4;  suranal  process 
short,  strongly  chitinized,  nearly  as  long  as  wide  at  proximal  end,  denti- 
form tubercles  with  circular  rows  of  stiff  setae  on  the  proximal  half,  distal 
half  small,  depressed,  narrowly  oblong  in  cross-section;  subanal  appendages 
peg-like,  with  a  minute  seta  at  the  distal  end,  apparently  segmented, 
without  setae  near  the  proximal  end;  lateral  area  of  suranal  lobe  with 
2-3  setae;  mandible  with  four  dentes. 

SPECIES  OF  JANUS 

Subanal  appendages  distinctly  two-segmented,  segment  1  ring-like,  much  larger  in  diameter 
than  segment  2;  antennae  with  segment  5  about  one-half  as  long  as  segment  4;  bores  in 
Salix  and  Populus abbreviaius  Say. 

Subanal  appendages  indistinctly  two-segmented,  segments  subequal  in  diameter;  antennae 
with  segment  5  subequal  in  length  to  or  only  slightly  shorter  than  segment  4;  bores  in 
Ribes  species  (currant);  C integer  Norton. 

Adirus  Konow 

Antennae  distinctly  with  four  segments;  segment  4  long,  peg-like, 
bluntly  pointed,  nearly  three  times  as  long  as  wide,  twice  as  long  as 
segment  3;  suranal  process  large,  distal  fourth  strongly  chitinized,  sud- 
denly constricted,  circular  in  cross-section,  with  chitinized  dentiform 
tubercles;  subanal  appendages  peg-like,  fleshy,  apparently  unsegmented, 
with  setae  near  the  proximal  end,  these  setae  separated  from  the  remainder 
of  the  setae  on  the  sternum;  lateral  area  of  suranal  lobe  with  20-28  setae. 

Adirus  trimaculatus  Say. — Middleton  has  described  the  larvae  in 
detail.  They  bore  in  the  stems  of  blackberry  and  rose.  Thru  the  kindness 
of  Dr.  E.  P.  Felt,  one  mature  and  two  young  damaged  specimens  from 


429]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  111 

the  New  York  State  Museum,  labeled  "a  2766"  and  "a  2261"  were  exam- 
ined by  me. 

Trachelus  Jurine 

Antennae  apparently  with  four  segments — according  to  Gahan  five 
segments  present;  body  thickest  dorso-ventrad  in  mesothorax,  second 
and  third  abdominal  segments  widest,  the  ninth  and  tenth  tapering 
suddenly;  suranal  process  rather  short,  tapering  caudad  gradually,  chit- 
inized  dentiform  tubercles  wanting,  with  or  without  stiff  short  setae, 
if  setae  present  they  do  not  arise  from  chitinized  bases;  ultimate  tergum 
setiferous  on  both  sides  of  the  median  depression,  convex  as  viewed  from 
side,  truncate  on  the  caudal  aspect,  not  declivous  caudad;  third  abdominal 
segment  with  three  annulets,  annulet  2  largest  and  with  a  transverse  row 
of  setae;  subanal  appendages  peg-like,  unsegmented. 

Trachelus  tabidus  Fabricius. — Suranal  process  without  distinct  con- 
striction, with  or  without  brownish  setae,  if  present,  setae  arranged  in  a 
irregular  circle  in  the  proximal  half;  subanal  appendages  brownish  with  2 
minute  setae  at  the  distal  end,  and  with  1  or  2  setae  which  are  separated 
from  the  remainder  of  the  setae  on  the  sternum;  lateral  area  of  suranal 
lobe  with  5-7  setae;  antennae  with  segment  4  bluntly  rounded,  segments 
2  and  3  ring-like,  segment  1  narrow  but  large  in  diameter  with  a  seta  on 
the  dorsal  margin,  segments  all  brown;  bore  in  the  stalks  of  wheat,  rye, 
and  barley  (Gahan  1920). 

Cephus  Latreille 

Antennae  apparently  with  four  segments — according  to  Middle- 
ton  five  segments  present — segment  4  less  than  twice  as  long  as  wide; 
abdominal  segments  5-8  with  ventral  swellings  corresponding  in  position 
to  larvapods;  suranal  process  without  chitinized  dentiform  tubercles,  either 
with  a  narrow  ring-like  distal  chitinized  portion  and  a  semicircular  row  of 
setae  or  with  a  long  cylindrical  distal  portion  and  two  or  more  irregular 
rows  of  whorls  of  setae  on  the  proximal  portion,  the  distal  margin  of  the 
distal  chitinous  portion  entire  and  smooth;  subanal  appendages  papilla- 
like, cylindrical,  more  than  twice  as  long  as  wide,  bluntly  rounded  at  the 
distal  end,  with  one  or  more  setae  near  the  proximal  end;  lateral  area  of 
suranal  lobe  with  7-15  setae;  mandible  with  three  dentes.  . 

According  to  Rohwer  (1917)  only  two  species  of  this  genus  are  known 
to  occur  in  North  America.    They  can  be  separated  as  follows: 

SPECIES  OF  CEPHUS 

Suranal  process  with  the  distal  chitinized  portion  cylindrical,  twice  as  long  as  wide,  setae  on 
the  proximal  portion  arranged  in  two  or  three  irregular  whorls;  subanal  appendages  with 
several  setae;  lateral  area  of  suranal  lobe  with  about  15  setae;  the  only  true  Nearctic 
species  known;  bores  in  stalks  of  Elymus,  Agropyron,  Phleum,  and  wheat,  cinctus  Norton. 


112  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [430 

Suranal  process  with  distal  chitinized  portion  ring-like,  shorter  than  wide,  setae  on  the 
proximal  portion  arranged  in  a  semicircular  row  on  the  dorsal  aspect;  subanal  append- 
ages with  one  or  rarely  two  setae,  lateral  area  of  suranal  lobe  typically  with  seven  setae; 
introduced  from  Europe;  bores  in  stalks  of  wheat pygmaeus  Linnaeus. 

Hartigia  Schiodte 

Antennae  apparently  with  four  segments — according  to  Middleton 
(1917)  with  five  segments — segment  4  longer  than  segment  3,  elongate, 
conical;  suranal  process  twice  as  long  as  wide  at  proximal  end,  without 
strongly  chitinized  dentiform  tubercles,  with  several  whorls  of  spinous 
setae;  subanal  appendages  two-segmented,  sometimes  segmentation 
indistinct,  with  accompanying  setae  separated  from  the  remainder  of 
setae  of  the  sternum;  lateral  area  of  suranal  lobe  with  15-20  setae. 

Hartigia  cressoni  Kirby. — The  larvae  of  this  species  have  been  described 
in  detail  by  Middleton.  They  bore  in  the  stems  of  Rubus  in  California. 
The  preceding  generic  definition  was  based  upon  specimens  obtained  thru 
the  courtesy  of  Mr.  Harry  S.  Smith,  of  Sacramento,  California,  and  does 
not  quite  agree  with  that  given  by  Middleton  (1917). 

Family  Xiphydriidae 

Larvae  (Fig.  3)  small;  body  subcylindrical,  thorax  and  two  caudal  seg- 
ments distinctly  swollen;  segmentation  distinct;  annulation  obsolete; 
creamy  white,  no  markings;  glabrous;  thoracic  legs  rudimentary,  fleshy, 
mamma-like,  without  tarsal  claws;  larvapods  wanting;  ultimate  segment 
with  distinct  suranal  process,  without  subanal  appendages;  ocellarae 
wanting;  mouth-parts  modified;  maxillary  palpi  apparently  two-segmented; 
antennae  apparently  with  three  segments;  metaspiracles  functionless,  very 
much  smaller  than  abdominal  spiracles;  cuticle  on  dorsum  smooth,  on 
venter  microscopically,  sharply,  and  densely  spinulate;  tenth  abdominal 
tergum  with  deep  meso-dorsal  depression;  wood-borers. 

The  Xiphydriidae  contains  four  genera,  Derecyrta,  Brachyxiphus, 
Xiphydria,  and  Konowia,  which  may  be  divided  into  two  groups  on 
the  presence  or  absence  of  the  radial  cross-vein  in  the  wings.  Systematists 
have  generally  considered  this  group  as  a  subfamily  of  the  Siricidae,  but 
MacGillivray  (1906)  has  elevated  it  to  its  present  standing  on  the  vena- 
tional  characters,  which  he  has  proven  to  be  the  most  generalized  of  the 
specialized  Tenthredinoidea.  Rohwer  (1911)  would  divide  the  family 
into  two  subfamilies,  Xiphydriinae  and  Derecyrtinae,  the  latter  being 
monobasic.    Of  the  four  genera,  two  are  represented  in  the  Nearctic  fauna. 

In  a  recent  synopsis  of  the  Nearctic  wood- wasps,  Rohwer  (1918b) 
tabulates  eight  species  of  Xiphydria.  He  considers  that  X.  walshii  West- 
wood,  which  MacGillivray  (1916)  assigned  to  the  genus  Konowia  belongs 
to  the  original  genus,  although  the  species  was  unknown  to  him,  and 
states  that  "it  is  possible  that  it  is  provancheri  Cresson."    Rohwer  suggests 


431]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  113 

that  the  specimens  which  Patten  (1878)  reared  from  Betula  nigra  and 
regarded  as  X.  attenuata  Norton  do  not  belong  to  this  species  but  are 
similar  to  an  undescribed  female  bearing  a  Bradley  manuscript  name. 
Nothing  is  known  concerning  the  immature  stages  of  Konowia  basalts 
Say.  The  larvae  of  Xiphydria  are  wood-borers  and  confine  their  attacks 
to  dead  and  decaying  wood  of  deciduous  trees.  European  species  infest 
willows,  poplar,  elm,  and  birch,  and  American  species,  maple,  hickory, 
and  birch.  Konow  (1901)  listed  four  species,  Xiphydria  prolongata,  X. 
camelus,  X.  longicollis,  and  X.  abdominalis  in  his  key  to  the  larvae  of 
Tenthredinoidea. 

Xiphydria  Fallen 

Larvae  comparatively  small;  thorax  distinctly  swollen,  the  meta- 
thorax  being  the  largest  segment  of  the  body;  abdominal  segments  1-2 
cylindrical,  subequal  in  diameter;  third  abdominal  segment  with  a  single 
annulet;  two  caudal  segments  somewhat  globose;  sublateral  lobe  moder- 
ately large,  extending  the  entire  length  of  the  segment;  suranal  process 
comparatively  long,  with  dentiform  tubercles  near  the  base;  tenth  ab- 
dominal sternum  much  smaller  than  the  tergum;  head  and  ultimate 
segment  with  long  setae;  head  semiglobose,  vertical  furrows  present; 
epicranial  suture  in  part  indistinct;  antennariae  distinct;  antennae  three- 
segmented,  segments  1  and  2  ring-like,  segment  3  conical,  longer  but  of 
much  smaller  diameter  than  the  preceding  segments;  labium  very  small, 
without  median  emargination;  mandibles  with  distinct  dentes;  maxillae 
with  small  modified  palpi,  apparently  two-segmented;  galea  conical, 
smaller  than  palpi,  lacinia  fleshy,  tubercle-like,  with  several  setae;  labium 
with  submentum  and  mentum  large,  convex,  membranous,  palpi  appar- 
ently with  three  segments,  small,  median  lobe  large,  flattened  on  venter, 
suboblong;  spiracles  large,  oblique,  not  winged;  glandubae  wanting. 

Xiphydria  provancheri  Cresson. — Length,  12  mm.;  width  of  head, 
1.6  mm.;  body  yellowish  white;  head  creamy  white;  mouth-parts  brownish; 
suranal  process  arising  from  large  brownish  strongly  chitinized  suranal 
lobe,  deep  brown,  at  proximal  end,  more  than  twice  as  long  as  wide, 
distal  two-thirds  suddenly  and  distinctly  smaller  in  diameter  than  proximal 
third,  with  two  circular  rows  of  dentiform  tubercles  and  setae  on  the 
proximal  third  and  two  distinct  ventral  dentiform  tubercles  on  the  distal 
third,  one  caudad  of  the  other,  these  without  setae;  on  birch. 

This  description  is  based  upon  a  rare  specimen  collected  at  Saranac 
Inn,  New  York  State,  Aug.  20,  1900,  and  generously  loaned  by  Dr.  E.  P. 
Felt.  The  larva  bores  into  partly  decayed  heartwood  of  standing  birch 
and  makes  a  gallery  about  2.5  mm.  in  diameter.  The  burrows  are  invari- 
ably filled  with  the  borings,  except  a  short  curved  portion  thru  which  the 
adult  makes  its  way  to  the  surface.  A  parasite,  Pammegischia  xiphydriae 
Ashmead,  was  reared  by  Dr.  Felt  from  larvae  of  this  species. 


114  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [432 

Dr.  Felt  (1906)  also  found  another  larva  making  moderately  large 
cylindrical  burrows  in  decaying  birch  and  considered  it  as  probably 
belonging  to  X.  attenuata.  He  refers  to  the  rearing  of  this  species  by 
Patton  and  suggests  Rhyssa  humida  Say  as  its  parasite.  Since  the  identity 
of  Patton's  specimen  is  questioned  and  since  the  adult  was  apparently 
not  reared,  it  is  not  possible  to  identify  the  specimen  under  consideration. 
If  it  were  really  X.  attenuata,  then  it  should  be  known  as  X.  abdominalis 
as  proposed  by  Konow  (1905)  and  Rohwer  (1918). 

Family  Siricidae 

Body  large,  30-40  mm.,  cylindrical,  uniform  in  diameter  thruout 
(Fig.  4),  fleshy,  plump;  integument  smooth,  transparent,  non-setaceous, 
light  in  color;  head  circular,  half  as  high  as  thorax;  mouth  directed  ventrad, 
mostly  exposed,  but  slightly  overlapped  by  prothorax;  antennae  incon- 
spicuous, apparently  one-segmented;  ocellarae  wanting;  epicranial  suture 
wanting  and  vertical  furrow  indistinct;  mouth-parts  not  normal  in  form, 
light  in  color;  prothorax  large;  mesothorax  and  metathorax  short  in 
comparison  with  abdominal  segments;  legs  rudimentary,  mamma-like, 
subequal  in  size,  borne  on  fleshy  conical  lobes;  larvapods  wanting;  typical 
segment  with  two  indistinct  annulets,  sublateral  lobe  distinct  but  not 
prominent;  tenth  abdominal  segment  semiglobose  in  profile;  tenth  tergum 
distinctly  depressed  by  a  median  furrow;  suranal  lobe  on  the  meson  with 
dark  colored,  chitinized,  suranal  process;  subanal  appendages  wanting;  in- 
ternal-feeder, bores  in  the  trunks  of  deciduous  and  evergreen  trees. 

The  Siricidae  contains  five  genera  and  about  fifty  species,  most  of 
which  are  confined  to  the  northern  hemisphere.  The  recognition  of  the 
fact  that  these  insects  constitute  a  well-circumscribed  group  dates  back 
to  the  time  of  Linnaeus  (1758)  who  described  five  species  of  Siricidae  among 
those  of  his  heterogeneous  genus  Ichneumon,  three  of  the  five  having 
become  the  types  of  three  modern  genera.  Systematists  have  universally 
agreed  in  considering  this  group  worthy  of  family  rank.  The  family 
falls  into  two  natural  divisions,  Siricinae,  including  three  genera,  Sirex, 
Urocerous,  and  Xeris,  and  Tremecinae,  embracing  two  genera,  Tremex 
and  Teredon.  The  genus  Xeris  was  associated  with  the  genera  composing 
the  Tremecinae  both  by  Ashmead  (1898)  and  Konow  (1905),  but  Rohwer 
(1911)  proposed  a  more  natural  arrangement,  placing  this  genus  in  the 
Siricinae.  Bradley  (1913)  definitely  divided  the  two  groups  on  the  number 
of  segments  of  labial  palpi  and  the  retention  of  cerci  in  the  adults. 

According  to  Bradley  (1913)  there  are  twenty  species  reported  for 
North  America,  representing  all  the  known  genera.  The  specific  charac- 
ters of  some  common  species,  as  Sirex  nigricornis,  Urocerus  cressoni,  and 
Tremex  columba,  are  subject  to  a  wide  range  of  variation  and  several 
varieties  have  been  described.    So  far  as  known,  the  larvae  of  the  Siricinae 


433]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  115 

are  wood-borers  attacking  conifers,  those  of  the  Tremecinae  boring  in 
deciduous  trees.  Tremex  columba,  or  three  races  of  this  species  which 
infest  maple,  elm,  apple,  pear,  beech,  oak,  and  sycamore,  are  the  best- 
known  examples.  The  food-plants  of  only  three  American  species  are 
known,  these  including  Sirex  cyanens  and  Urocerus  albicornis.  Larvae  of 
the  Siricinae  have  not  been  examined. 

Tremex  Jurine 
Larvae  conspicuously  large;  body  cylindrical,  slightly  flattened  on 
the  venter;  large,  robust,  usually  bare  except  on  head  and  tenth  abdominal 
segment;  whitish  or  creamy  white;  setae  microscopic;  head  semiglobose, 
slightly  wider  than  high  on  cephalic  aspect,  semicircular  in  profile,  pro- 
duced to  the  ventral  half  of  the  front,  then  suddenly  truncated,  pale  brown- 
ish; mandibles  and  coilae  deep  brown;  antennae  apparently  one-segmented, 
conical;  antacoria  partly  chitinized  and  bearing  a  few  small  setae;  ocel- 
larae  wanting;  depression  mesad  of  antennaria  which  is  sometimes  called 
the  "eye"  is  a  pretentorina;  vertical  furrows  concealed  by  overhang- 
ing pro  thorax;  clypeus  small,  light  in  color;  labrum  transverse,  con- 
vex, thick,  asymmetrical,  without  median  emargination,  but  with  a 
notch  on  the  right  third  of  slightly  oblique  cephalic  margin;  mandibles 
strong;  mandacuta  distinct,  brown;  mandibularia  narrow,  inconspicu- 
ous, maxilla  fleshy  except  subgalea,  stipes  large;  palpi  two-segmented, 
small;  galea  conical,  brown,  small,  arising  from  broad  shoulder  which 
bears  a  few  tiny  setae  on  the  lateral  portion;  lacinia  round,  lobe-like, 
bearing  three  rows  of  brown  setae,  which  decrease  in  length  on  cephalic 
or  dorsal  side;  labium  compact,  submentum  narrow,  transverse,  mem- 
branous, mentum  convex,  lobe-like,  deeply  emarginate  on  cephalic  margin, 
ligula  round,  fitting  into  the  emargination  of  mentum,  palpi  small,  two- 
segmented,  second  segment  much  smaller  than  first,  conical  and  brown, 
sericos  large,  transverse,  distinct,  crescentic;  prothorax  large,  produced 
dorsad  and  cephalad,  overlapping  the  caudal  third  of  the  head;  mesothorac- 
ic  and  metathoracic  segments  about  one-half  the  length  of  abdominal  seg- 
ments except  the  first  abdominal  which  is  only  little  longer  than  the  meta- 
thorax;  thoracic  legs  rudimentary,  mamma-like,  short,  tipped  with  tiny 
chitinized  spot,  borne  on  fleshy  conical  pedal  lobe;  cervical  sclerites  want- 
ing; sternum  with  transverse  subtriangular  lobes  which  meet  on  the  meson 
in  front  of  median  lobe  between  and  slightly  cephalad  of  prothoracic  legs; 
metaspiracles  as  large  as  abdominal  spiracles;  abdomen  slightly  and  uni- 
formly tapering  to  the  caudal  end;  annulation  indistinct  on  dorsum, 
apparently  with  but  one  annulet,  the  venter  with  two  annulets,  the 
second  annulet  larger  than  the  first;  sublateral  lobe  prominent,  extending 
the  entire  length  of  segment  as  a  single  oblique  elevation;  spiracles  large, 
brown;  ninth  abdominal  segment  a  little  shorter  than  the  eighth;  tenth 


116  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [434 

tergum  convex,  lateral  area  of  suranal  lobe  broad,  suranal  process  promi- 
nent, deep  brownish,  strongly  chitinized,  compressed,  with  two  pairs  of 
small  but  distinct  teeth. 

The  foregoing  definition  of  the  genus  is  based  on  one  species,  Tremex 
columba. 

Tremex  columba  Linnaeus. — Length,  40  mm.;  width  of  head,  4  mm.; 
ultimate  segment  with  setae  as  follows:  tergum  near  the  caudal  margin 
on  each  side  of  the  median  furrow  with  a  small,  brown,  sharp,  hook-like 
spine,  with  tiny  setae  which  arise  from  large  calices;  ventral  side  of  suranal 
lobe  with  such  setae;  tenth  sternum  small;  small  brown  spot  at  the  lateral 
end  of  anal  slit;  subanal  lobe  non-setiferous;  subanal  appendages  wanting; 
1-8396;  G-. 

The  eggs  of  the  Pigeon  Tremex  are  oblong-oval,  pointed  at  both  ends 
about  1.2  mm.  in  length,  deposited  singly,  but  in  limited  area,  close  to  each 
other;  oviposition  takes  place  in  early  summer,  female  sometimes  fails  to 
withdraw  ovipositor  and  dies  in  situ;  larvae  on  hatching  in  the  wood  make 
a  gallery  and  feed  for  probably  one  season;  transformation  takes  place  in 
the  burrow;  adults  emerge  thru  circular  hole,  about  8  mm.  in  diameter. 
The  larvae  are  parasitizec  by  Thalessa  lunator  and  also  by  Megarhyssa 
atrata  Fabricius,  according  to  Champlain  (1921). 

Felt  (1906)  suggests  as  remedial  measure  against  this  insect,  the  cutting 
down  and  burning  of  all  trees  badly  infested.  Keeping  the  trees  in  vigor- 
ous health  is  supposed  to  be  sufficient  to  prevent  injury  as  the  larvae  work 
only  in  weakened  or  partly  decaying  wood. 

Family  Megalodontidae 

Antennae  long,  conspicuous,  multisegmented,  located  above  or  near 
the  ocellarae;  larvapods  wanting;  last  abdominal  segment  rounded,  with  a 
pair  of  bristle-like  segmented  subanal  appendages;  larvae  feed  on  herba- 
ceous plants. 

This  family  contains  four  genera,  Rhipidioceros,  Megalodontes, 
Melanopus,  and  Tristactus,  and  about  thirty-five  species,  which  are 
distributed  in  Europe,'  Asia,  and  North  Africa.  Systematists  have  invari- 
ably associated  this  family  with  the  Pamphiliidae,  but  that  this  position  is 
unnatural  has  been  conclusively  shown  by  MacGillivray.  He  has  pointed 
out  that  it  represents  a  line  of  specialization  very  similar  to  that  found 
in  the  Siricidae,  and  that  while  it  is  more  closely  related  to  this  family 
than  to  any  other,  an  abundance  of  characters  justify  one  in  considering 
it  as  a  distinct  group. 

Only  one  species,  Megalodontes  spissicornis  Klug  has  been  recognized 
in  the  larval  stage.  The  larvae,  according  to  Hiendlmayr  (1878),  are  found 
on  Lasperfritium  latifolium  L.  in  central  Europe  from  the  end  of  July  to 


435]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  117 

the  beginning  of  August.  In  the  younger  stages,  they  are  gregarious 
and  live  in  a  common  nest  like  many  Pamphiliidae,  but  they  spin  an 
individual  web  when  half-grown.    There  is  one  generation  a  year. 

This  interesting  species  was  not  available  for  study,  and  the  foregoing 
definition  is  abstracted  from  Konow  (1901)  and  may  be  found  by  later 
students  of  little  value  in  defining  the  family.  This  family,  so  far  as  the 
recorded  larval  characters  are  concerned,  seems  to  be  closely  associated 
with  the  Pamphiliidae  in  possessing  the  bristle-like  subanal  appendages 
and  long  conspicuous  antennae.  Future  observations,  however,  may 
possibly  reveal  more  important  characters,  not  given  in  the  brief  synopsis 
of  Konow. 

Family  Oryssidae 

Body  (Fig.  5)  eruciform,  grub-like,  subcylindrical,  slightly  depressed, 
swollen  in  the  middle  of  the  abdomen,  tapering  at  each  end;  segmentation 
distinct;  annulation  obsolete;  creamy  white,  without  colored  markings; 
spiracles  on  prothorax  and  first  eight  abdominal  segments;  thorax  increas- 
ing in  size  caudad,  thoracic  legs  obsolete;  larvapods  wanting;  fourth 
abdominal  segment  largest  in  diameter,  size  of  segments  decreasing  rapidly 
caudad,  last  segment  smallest;  suranal  process  and  subanal  appendages 
wanting;  head  white,  compressed  cephalo-caudad,  circular  in  frontal 
contour,  narrower  than  thorax;  antennae  with  a  single  segment,  papilla- 
like; mandibles  tridentate;  maxillae  and  labium  vestigial,  fleshy,  lobe-like, 
without  palpi;  ocellarae  wanting;  larvae  parasitic  on  wood-boring  larvae  of 
Coleoptera;  pupation  in  the  pupal  cells  of  the  hosts. 

The  Oryssidae  contain  six  genera  and  a  limited  number  of  species 
distributed  thruout  the  world.  The  genus  Oryssus  alone  is  represented 
in  the  Nearctic  region.  In  former  years  the  family  has  been  associated 
with  the  Siricidae,  but  recently  writers  are  in  accord  in  regarding  it  as  an 
extremely  specialized  compact  group.  MacGillivray  (1906)  came  to  the 
conclusion  that  "so  far  as  their  wings  are  concerned  the  presence  of  the 
second  anal  cell  in  the  front  wings  is  the  only  structure  that  would  place 
the  genus  Oryssus  in  the  superfamily  Tenthredinoidea" ;  The  group  is 
not  only  highly  specialized  in  the  adult  characters  but  a  recent  discovery 
of  the  parasitic  habit  of  the  larvae  isolates  these  Hymenoptera  from  all 
other  Tenthredinoidea  as  a  unique  class.  In  fact  Rohwer  and  Cushman 
(1917)  have  gone  so  far  as  to  propose  a  new  suborder,  Idiogastra,  placing  it 
"intermediate  between  the  suborder  Chalastogastra — where  adult  would 
place  it — and  the  suborder  Clistogastra — with  which  the  larva  would  ally 
it."  Whether  this  arrangement  is  acceptable  or  not,  the  fact  that  this 
group  is  remarkably  well  circumscribed  and  that  it  represents  the  summit 
of  an  extremely  isolated  line  of  specialization  in  the  Tenthredinoidea 
can  not  be  doubted. 


118  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [436 

Only  one  species,  Oryssus  occidentalis  Cresson,  has  been  recognized  in 
the  immature  stages.  The  definitions  given  here  are  based  on  the  descrip- 
tions and  figures  of  this  species  published  by  Rohwer  and  Cushman  (1917). 
It  is  quite  possible  that  future  studies  may  prove  them  inadequate  for 
the  identification  of  the  larvae  of  other  genera  and  species  yet  to  be  dis- 
covered. 

Oryssus  Latreille 

Larvae  small;  epicranial  suture  faint,  arms  obsolete;  clypeus  cres- 
centic,  narrow;  fronto-clypeal  and  clypeo-labral  sutures  distinct;  labrum 
more  than  twice  as  wide  as  long,  with  shallow  mesal  emargination;  an- 
tennaria  distinctly  elevated,  antacoria  extensive,  mound-like;  antennae 
small,  mamma-like;  mandibles  strongly  chitinized,  curved,  narrow  mesal 
dentis  larger  than  lateral  dentes,  these  subequal  in  size,  sharp;  maxillae 
fleshy,  sub  triangular,  unsegmented  lobes;  annulation  on  dorsum  indistinct, 
with  apparently  two  annulets,  venter  with  one;  sublateral  lobes  distinct, 
extending  the  entire  length  of  the  segments;  spiracles  visible  from  dorsal 
aspect;  segments  transversely  raised  and  with  a  few  minute  tubercles. 

Oryssus  occidentalis  Cresson. — Color  white  with  mandibles  and  chit- 
inized ridges  near  the  mouth  brown;  head  one-third  as  wide  as  the  widest 
segment  of  the  body — the  fourth  abdominal  segment;  maxillae  with  minute 
brownish  spots  bearing  about  three  sensory  papillae;  labium  with  about 
four  stout  setae  on  each  side  of  meson;  prothorax  declivous  toward  the 
head,  forming  straight  line  with  the  latter  in  profile,  on  dorsum  subequal 
in  length  to  mesothorax;  metathorax  half  as  long  as  mesothorax;  lengths 
of  abdominal  segments  as  follows:  8,  (1,  9),  (2,  7),  (4,  6),  5,  10  on  dorsum, 
(6,  7,  8),  5, 1,  3,  (2,  4),  9,  10  on  venter,  8,  7,  4,  (1,  2,  5,  6),  3,  9,  10  on  latus; 
tenth  abdominal  segment  one-fourth  as  wide  and  one-third  as  high  as  the 
fourth  and  sixth  segments  respectively;  dorso-cephalic  margin  of  mesothor- 
acic  and  eighth  abdominal  segments  distinctly,  and  of  metathoracic  and 
abdominal  segments  5,  6,  7,  9,  10  slightly  convex,  and  of  abdominal 
segments  2  and  3  concave;  ventro-cephalic  margin  of  abdominal  segments 
1,  6,  7,  8  distinctly,  and  of  2  and  9  slightly,  concave,  of  3,  4,  and  5  convex, 
of  1  and  6  with  a  distinct  convex  emargination  on  each  side  of  meson; 
abdominal  segments  with  the  distance  from  spiracles  to  dorsal  surface 
uniform  on  lateral  aspect  and  much  shorter  than  the  distance  from  spiracles 
to  the  ventral  surface,  the  latter  variable  and  increasing  caudad  to  the  sixth 
segment  and  diminishing  thereafter;  "each  thoracic  and  abdominal  segment 
has  dorsally  at  each  side  of  the  middle  a  low,  transverse  elevation  sur- 
mounted by  a  transverse  row  of  four  or  five  short,  stout  back-pointing 
spines";  setiferous  elevations  on  abdominal  segments  1-7  and  9  and  on 
metathorax  near  the  caudal  margin  of  the  segments,  those  of  prothoracic 


437]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  119 

and  mesothoracic  and  eighth  abdominal  segments  being  in  the  middle; 
tenth  abdominal  segment  with  small  pointed  protuberances  directed  cau- 
dad;  venter  of  segments  with  brownish  spots  in  place  of  legs;  larvae  para- 
sitic on  the  larvae  of  Buprestis  confluens  Say,  B.  laeventris  Le  Conte,  and 
possibly  other  species  of  Buprestidae. 


120  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [438 


IV.    PHYLOGENY 

A  classification  based  on  phylogeny  is  one  of  the  essential  concerns  of 
philosophical  taxonomy.  In  order  to  ascertain  the  genetic  relationship 
of  organisms,  synthetic  as  well  as  analytic,  consideration  of  evidence 
drawn  from  all  the  branches  of  biological  science  is  imperative.  The 
indissoluble  relation  of  morphology,  embryology,  and  paleontology  to  tax- 
onomy is  so  manifest  and  familiar  that  no  comments  are  needed.  The 
time  has  come,  however,  when  a  critical  examination  of  the  phylogenetic 
significance  and  the  taxonomic  value  of  the  physiological  and  biological 
attributes  of  animals  must  be  made.  Whatever  evidence  comparative 
physiology,  biochemistry,  and  genetics  may  offer  should  be  incorporated 
as  far  as  possible  with  the  data  obtained  in  other  more  commonly  ex- 
ploited fields  of  research.  Only  in  this  way  is  it  possible  to  arrive  at  a 
comprehensive,  systematic  and  complete  summation  of  knowledge  of 
animals.  This  is  the  primary  function  of  philosophical  taxonomy,  and  in 
this  sense  the  saying  of  W.  S.  Jevons  that  "science  can  extend  only  so  far 
as  the  power  of  accurate  classification  extends,"  is  true. 

There  are  good  reasons  to  believe,  however,  that  even  to-day  morphol- 
ogy, as  of  old,  holds  its  supreme  place  in  systematic  investigations  as  it 
offers  fundamental  assistance  in  determining  the  genetic  affinities  of 
organisms.  The  success  of  a  study  of  phylogeny  based  on  morphological 
evidences  depends  on  the  ability  of  the  investigator  to  select  the  proper 
structures,  to  determine  the  direction  and  nature  of  changes  undergone  by 
these  structures,  and  to  draw  legitimate  conclusions  by  judicious  interpre- 
tation of  the  facts  observed.  Data  obtained  from  studies  of  the  external 
anatomy  of  the  larval  stages  of  entometabolous  insects  are  of  necessity 
incomplete  of  themselves  for  determining  the  phylogeny  of  the  group; 
yet,  in  the  absence  of  other  means  of  approach  to  the  problem,  they 
constitute  essential  facts  significant  enough  to  merit  careful  consideration. 

The  opinions  of  scientists  in  regard  to  the  systematic  importance  of 
the  characters  based  upon  the  immature  stages  of  Entometabola  have 
been  divided.  There  are  some  who  ascribe  no  importance  whatsoever  to 
them  and  entirely  ignore  this  phase  of  taxonomy.  There  are  others  who 
recognize  the  importance  of  the  larvae  from  the  viewpoint  of  synoptic 
classification  as  they  are  primarily  interested  in  the  practical  purpose  of 


439]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  121 

synoptic  descriptions  and  keys.  There  are  still  others  who  believe  in  the 
intrinsic  importance  of  the  immature  stages  in  the  study  of  phylogeny. 
The  reasonableness  of  the  oft-repeated  objection  which  was  voiced  by 
Comstock  (1918)  that  the  larvae  of  insects  exhibit  a  cenogenetic  develop- 
ment and,  therefore  their  ontogeny  bears  little  or  no  relation  to  the  phylog- 
eny of  the  race,  must  be  admitted  in  regard  to  certain  structures  which 
are  entirely  too  adaptive  and  too  much  modified  by  environmental  factors 
in  meeting  the  trophic  requirements  of  particular  species  or  genera.  But 
admission  of  this  fact  is  not  incompatible  with  a  belief  in  palingenesis 
of  other  structures.  Besides,  the  warning  that  the  cenogenetic  peculiari- 
ties, which  may  be  of  value  as  distinguishing  characters,  are  of  no  phylo- 
genetic  significance  and  must,  therefore,  be  judiciously  and  discriminately 
distinguished  from  more  important  palingenetic  characters,  applies  not 
only  to  the  classification  of  the  larvae  but  to  the  taxonomy  of  the  adults  as 
well.  This  objection  alone  does  not  invalidate  a  belief  in  the  intrinsic 
importance  of  the  immature  stages  from  the  phylogenetic  point  of  view. 
While  the  writer  does  not  minimize  the  danger  of  a  too  confident  expecta- 
tion of  finding  phylogenetic  indices  in  the  successive  ontogenetic  stages  in 
entometabolous  insects,  yet  he  is  equally  reluctant  to  abandon  his  hope  in 
regard  to  the  taxonomic  value  of  the  characters  of  immature  insects. 
The  present  study  is  a  partial  justification  of  his  contention. 

Students  of  the  Tenthredinoidea  have  recognized  the  practical  im- 
portance of  the  larvae  in  determining  the  systematic  position  of  different 
taxonomic  units.  Norton  (1867)  stated  that  "Mr.  Walsh  has  shown 
that  in  some  species  of  Euura  and  Nematus  bred  by  him,  it  was  almost 
impossible  to  detect  any  difference  in  the  imago,  while  the  larvae  varied 
greatly.  Doubtless  our  opinion  will  be  greatly  modified  by  future  dis- 
coveries." Cameron  (1882)  was  of  the  opinion  that  the  larvae  were  of 
great  value  in  differentiating  the  tribes  and  subtribes  altho  they  appeared 
to  be  of  little  use  in  regard  to  the  genera.  MacGillivray  (1913)  goes  further 
and  states  that  "it  was  hoped  from  a  study  of  the  immature  stages  of  the 
Tenthredinoidea  that  some  information  might  be  obtained  as  to  the 
validity  of  the  species  based  on  obscure  anatomical  details."  Rohwer 
also  often  uses  the  characters  of  the  larvae  as  collateral  evidence  in  decid- 
ing the  systematic  position  of  certain  subfamilies  and  genera. 

Nothing  definite  is  known  in  regard  to  the  ancestors  of  the  Hymenop- 
tera  beyond  the  probability  that  they  have  somehow  arisen  from  a  primi- 
tive type  of  some  neuropteroid-like  Palaeodictyoptera.  The  order  is 
considered  to  be  one  of  the  most,  if  not  the  most,  highly  specialized  of  all 
insects.  Systematists  are  unanimous  in  regarding  the  Tenthredinoidea 
as  the  most  generalized  of  the  Hymenoptera.  It  is  difficult,  if  not  impossi- 
ble, to  conjecture  the  primitive  larval  type  of  the  Tenthredinoidea. 
Judging,  however,  from  what  are  universally  considered  to  be  generalized 


122  ILLINOIS  BIOLOGICAL  MONOGRAPHS  {440 

conditions  in  insects  in  general  and  in  the  Tenthredinoidea  in  particular, 
the  probable  ancestral  type  of  larva  may  be  characterized  as  follows: 
body  cylindrical;  segmentation  distinct;  annulation  indistinct,  annulets 
few  in  number;  head  exposed,  subglobose,  distinct  from  the  trunk;  thorax 
and  abdomen  more  or  less  similar  in  structure  excepting  the  three  pairs  of 
thoracic  legs,  which  are  well  developed  and  consist  of  five  segments, 
tarsal  claws  distinct;  abdomen  with  twelve  segments  including  the  telson; 
larvapods  present  on  abdominal  segments  1-10;  antennae  long,  composed 
of  several  segments;  ocellarae  present,  one  on  each  side  of  head;  mouth- 
parts  well  developed,  maxillary  and  labial  palpi  segmented;  tenth  abdom- 
inal tergum  without  caudal  protuberances  or  suranal  process;  eleventh 
abdominal  sternum  with  a  pair  of  segmented  subanal  appendages;  ten 
pairs  of  functional  spiracles  present,  including  metaspiracles;  larvae  free 
leaf-feeders. 

There  are,  as  was  pointed  out  by  Comstock  (1893),  two  kinds  of  char- 
acters of  phylogenetic  importance.  "First,  characters  indicating  differ- 
ence in  kind  of  specialization;  and  second,  characters  indicating  difference 
in  degree  of  specialization  of  the  same  kind.  The  former  will  indicate 
dichotomous  divisions  of  lines  of  descent;  the  latter  merely  indicate 
degrees  of  divergence  from  a  primitive  type." 

In  determining  the  probable  genetic  affinities  of  the  families  of  the 
Tenthredinoidea,  the  following  structures  have  been  taken  into  considera- 
tion: thoracic  legs,  larvapods,  subanal  appendages,  ocellarae,  antennae, 
mouth-parts,  suranal  process,  and  metathoracic  spiracles.  The  list  does 
not  by  any  means  exhaust  the  structures  which  might  be  employed  for 
this  purpose,  but  it  is  believed  that  the  structures  listed  offer  the  most 
reliable  and  essential  basis  for  the  determination  of  a  phylogeny  based 
upon  larval  characters.  The  significant  changes  in  these  structures  are: 
addition  or  reduction  of  parts;  difference  in  degrees  of  development  of 
existing  parts;  and  modifications  in  length,  size,  shape,  and  degree  of 
chitinization  of  the  parts.  These  modifications  have  been  interpreted 
according  to  the  Comstockian  principles  quoted  above. 

The  thoracic  legs  are  among  the  most  persistent  structures  in  the 
adult  and  larval  stages  of  insects  in  general,  and  their  absence  is  unques- 
tionably an  indication  of  specialization  by  reduction.  It  is  likewise 
reasonable  to  assume  that  any  modification  of  the  typical,  simple,  cylin- 
drical, five-segmented  condition  as  regards  the  form  or  the  number  of 
segments  is  a  sign  of  specialization.  The  legs  of  the  larvae  of  the  Pam- 
philiidae  approximate  most  closely  the  primitive  condition  in  the  number, 
shape,  and  structure  of  the  segments.  The  tarsal  claw  is  straight  and 
very  slender.  In  the  Xyelidae  the  legs  assume  a  condition  different  from 
that  of  the  Pamphiliidae.  The  differentiation  of  segments  in  size  and  shape 
has  proceeded  further  and  the  tarsal  claws  have  become  distinctly  claw- 


441]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  123 

like.  The  legs  are  very  small  compared  with  the  size  of  the  body.  The 
Tenthredinidae  present  a  series  of  conditions  which  illustrate  beautifully 
cases  of  modification  both  by  reduction  and  addition.  The  typical,  well- 
developed,  five-segmented  legs  undoubtedly  represent  the  normal  sequence 
in  development  from  the  condition  found  in  the  Xyelidae.  The  apparently 
six-segmented  condition  of  the  Hylotominae,  four-segmented  legs  of  the 
Fenusinae,  and  three-segmented  condition  of  the  Schizocerinae,  together 
with  the  development  of  distal  fleshy  lobes  in  the  first-  and  last-named 
subfamilies  are  cases  of  specialization.  The  fact  that  the  specialization 
by  reduction  of  segments  has  not  proceeded  at  the  same  rate  in  the  last 
two  subfamilies  is  indicated  by  the  difference  in  the  structure  of  the 
segments.  It  is  interesting  to  note  that  the  prothoracic  legs  of  the  Schizo- 
cerinae still  retain  four  segments  in  spite  of  the  fact  that  in  the  two  caudal 
pairs  the  number  of  segments  has  been  reduced  to  three.  The  osculant 
genus  Phlebatrophia  is  unique  among  all  other  Tenthredinidae  in  having 
the  legs  modified  to  such  an  extent  as  to  lose  all  resemblance  to  normal 
segmented  legs.  They  have  become  mere  fleshy,  indistinctly  segmented, 
clawless  protuberances.  In  this  character  this  genus  resembles  highly 
specialized  families  such  as  the  Cephidae  and  its  allies.  The  Cephidae, 
Xiphydriidae,  and  Siricidae  represent  a  series  of  modifications  in  which  the 
changes  have  resulted  in  fleshy,  vestigial,  entirely  clawless  legs  with  or  with- 
out indication  of  segmentation.  Judging  from  the  size  and  degree  of 
segmentation,  the  Xiphydriidae  is  more  generalized  than  the  Siricidae 
and  more  specialized  than  the  Cephidae.  The  Oryssidae  is  entirely  apo- 
dous,  and  the  fact  that  it  is  parasitic  on  buprestid  larvae  leaves  no  doubt 
as  to  its  extreme  specialization. 

The  larvapods  are  considered  as  true  appendages  of  the  abdominal 
segments.  Their  presence  is  highly  significant  from  a  phylogenetic  point 
of  view.  The  larvae  of  the  Tenthredinoidea  are  divisible  into  two  types 
according  to  the  presence  or  absence  of  the  larvapods.  The  Xyelidae 
and  Tenthredinidae  represent  the  type  with  polypodous  larvae  and  the 
other  five  families  represent  the  type  with  apodous  larvae.  In  the  first 
group  the  Xyelidae  possess  the  maximum  number,  or  ten  pairs,  of  larva- 
pods, while  the  Tenthredinidae  are  provided  with  six  to  eight  excepting 
certain  specialized  genera  which  possess  very  vestigial  or  no  larvapods. 
It  has  not  been  possible  to  determine  the  reason  for  the  invariable  absence 
of  larvapods  upon  the  first  and  ninth  uromeres  in  the  Tenthredinidae.  It 
may  be  that  the  same  mechanical  factors  which  have  caused  the  fusion 
of  anal  larvapods  in  boring  larvae  like  Caulocampus  are  also  responsible 
for  this  condition.  The  size  and,  to  some  extent,  the  structure  and  position 
of  the  larvapods  vary  within  the  Tenthredinidae  as  in  the  Schizocerinae, 
Hylotominae,  and  Fenusinae.  It  is  interesting  to  note  that  the  gall-making 
genus  Pontania  retains  normal  larvapods  as  well  as  thoracic  legs,  while  the 


124  ILLINOIS  BIOLOGICAL  MONOGRAPHS  f442 

leaf-miners  have  both  thoracic  and  abdominal  legs  reduced  in  the  number 
and  size  of  their  segments.  The  small  size  and  reduced  number  of  seg- 
ments are  correlated  with  the  well-developed  thoracic  legs  of  the  Hylo- 
tominae.  In  this  subfamily  the  claws  are  very  large,  sharply  curved,  and 
provided  with  empodia-like  distal  structures,  indicating  a  great  adapta- 
tion for  clinging  to  leaves.  This  fact  is  sufficient  to  account  for  the  reduc- 
tion of  the  larvapods.  The  Pamphiliidae  and  four  specialized  families 
in  the  same  line  of  development  are  entirely  without  larvapods.  It  is 
highly  desirable  to  determine  whether  this  apodous  condition  signifies 
a  common  origin  of  all  five  families.  Upon  this  question  hinges  much  of 
the  interpretation  of  the  phylogeny  of  the  Tenthredinoidea. 

In  characterizing  the  larvae  of  the  hypothetical  primodial  Ten- 
thredinoidea the  abdomen  was  considered  as  provided  with  the  maximum 
number  of  appendages,  including  ten  pairs  of  larvapods  and  a  pair  of 
subanal  appendages.  This  assumption  is  based  upon  the  fundamental 
fact  that  the  progenitor  of  insects  having  evolved  from  a  typical  arthro- 
podan  organism  possessed  the  typically  arthropodan  character,  abdominal 
appendages.  This  assumption  is  justifiable  in  view  of  the  following  facts: 
(1)  the  possession  of  appendages  on  all  of  the  abdominal  segments  is  a 
fundamental  arthropodan  characteristic;  (2)  the  embryos  of  practically  all 
insects  exhibit  at  some  time  during  their  development  rudiments  of 
abdominal  appendages;  (3)  appendages  are  present  on  all  or  some  of  the 
abdominal  segments  in  the  postembryonic  stages  of  the  Apterygota; 
(4)  the  gonapophyses  of  the  Exometabola  represent  the  true  abdominal 
appendages  in  this  group  of  insects;  (5)  the  larvapods  and  other  appenda- 
ges are  present  in  the  larvae  of  the  Mecoptera,  Lepidoptera,  generalized 
Hymenoptera,  and,  possibly,  in  some  other  orders, — all  these  facts  indi- 
cating the  wide  occurrence  and  fundamental  continuity  of  abdominal 
appendages  in  the  Hexapoda.  It  is,  therefore,  not  unreasonable  to  assume 
that  the  progenitor  of  insects,  at  least  in  some  stage  of  its  development, 
possessed  appendages  on  all  of  the  abdominal  segments.  The  same 
argument  supports  the  contention  that  the  ancestors  of  the  Hymenoptera 
undoubtedly  closely  resembled  the  remoter  ancestors  of  the  Insecta. 
The  larvae  of  the  progenitor  of  the  Hymenoptera  for  this  reason  have 
been  considered  as  provided  with  the  maximum  number,  or  ten  pairs, 
of  larvapods,  a  pair  on  each  of  the  first  ten  abdominal  segments  and  a 
pair  of  subanal  appendages  on  the  eleventh  abdominal  segment.  If  this 
assumption  is  true,  the  larvae  of  the  Xyelidae,  which  possess  ten  pairs  of 
larvapods,  must  be  considered  as  representing  the  most  primitive  condition 
found  in  the  Hymenoptera.  Graber  (1890)  has  shown  that  in  the  larvae 
of  Hylotoma  the  larvapods  arise  from  the  embryonic  limb-rudiments  and 
are  directly  evolved  from  them  during  the  development  and,  therefore, 
the  larvapods  are  the  true  appendages  of  the  abdomen,  homodynamous 


443J  LARVAE  OF  THE  7 ENTHREDINOIDEA—YUASA  125 

with  the  thoracic  legs  and  homologous  with  the  abdominal  appendages  of 
generalized  insects.  There  is  no  reason  for  considering  the  larvapods  of 
the  Xyelidae  as  embryologically  and  morphologically  different  from  those  of 
Hylotoma,  consequently  the  larvapods  of  the  Xyelidae  must  be  the 
true  appendages  of  the  abdomen;  and  since  the  larvae  of  this  family 
are  provided  with  the  maximum  number  of  larvapods,  they  must  be 
considered  as  the  most  generalized  of  the  Tenthredinoidea.  The  Ten- 
thredinidae  with  six  to  eight  pairs  of  larvapods  and  certain  other  mor- 
phological and  biological  characters  are  unquestionably  related  to  the 
Xyelidae  and  probably  represent  a  line  of  evolution  from  a  xylelid-like 
ancestral  stock.  Among  the  Tenthredinoidea  with  apodous  larvae,  the 
Pamphiliidae,  with  a  pair  of  segmented  subanal  appendages,  is  undoubtedly 
the  most  generalized  of  all  five  families.  The  origin  of  the  Pamphiliidae 
is  consequently  an  important  question.  For  the  reasons  already  stated 
in  connection  with  the  larvapods,  the  progenitor  of  the  Hymenoptera  has 
been  considered  as  possessing  a  pair  of  subanal  appendages  on  the  caudal 
segment  of  the  body.  In  this  character  as  well  as  in  all  others  the  Pamphilii- 
dae approach  most  nearly  the  primitive  condition  and,  except  for  the 
absence  of  larvapods,  unquestionably  represents  the  most  generalized 
condition  found  in  the  Tenthredinoidea,  outranking  even  the  Xyelidae. 
The  loss  of  larvapods  in  this  case  is  just  as  difficult  to  explain  as  the  loss 
of  subanal  appendages  in  the  case  of  the  Xyelidae.  These  structures,  the 
larvapods  and  subanal  appendages,  must  have  been  lost  during  the  course 
of  phylogeny  since  the  progenitor  undoubtedly  possessed  both  of  these 
structures,  and  these  two  families,  in  spite  of  their  generalized  conditions, 
must  represent  the  end-products  of  evolution  in  their  particular  lines. 
It  is,  then,  natural  and  proper  to  assume  that  there  have  taken  place  two 
distinct  lines  of  development  from  the  ancestral  type  of  the  Hymenoptera. 
In  the  one,  the  specialization  consisted  in  the  suppression  of  the  develop- 
ment of  larvapods,  as  in  the  Pamphiliidae,  and  in  the  other  in  the  suppres- 
sion of  the  development  of  subanal  appendages,  as  in  the  Xyelidae.  These 
two  families,  then,  represent  two  independent  lines  of  evolution  and  are 
the  most  generalized  families  not  only  of  the  Tenthredinoidea  but  of  the 
Hymenoptera.  Whether  the  Xyelidae  is  more  generalized  than  the 
Pamphiliidae,  or  vice  versa,  must,  from  the  very  nture  of  the  case,  remain 
a  question  till  the  advancement  of  our  knowledge  shall  perhaps  make  the 
answer  possible.  There  are,  however,  a  few  things  that  should  be  pointed 
out  regarding  this  question.  If  the  suppression  of  the  development  of 
larvapods  is  considered  of  equal  phylogenetic  significance  with  the  sup- 
pression of  the  development  of  the  subanal  appendages,  and  if  the  head 
and  the  appendages  of  these  two  families  alone  are  compared,  there  is  no 
doubt  that  the  Pamphiliidae  are  more  generalized  than  the  Xyelidae. 
But  since  the  subanal  appendages  are  true  abdominal  appendages  homo- 


126  ILLINOIS  BIOLOGICAL  MONOGRAPHS  {444 

dynamous  with  the  larvapods,  and  since  it  is  natural  to  believe  that  the 
process  of  reduction  has  taken  place  very  slowly  by  gradual  suppression 
of  the  appendages,  it  is  not  unreasonable  to  assume  that  the  apodous 
condition  found  in  the  Pamphiliidae  represents  a  much  later  stage  of 
specialization  than  the  condition  of  the  polypodous  larvae  of  the  Xyelidae. 
The  biology  of  the  Pamphiliidae  also  indicates  that  this  family  is  perhaps 
more  specialized  than  the  Xyelidae.  However,  these  considerations 
counterbalance  each  other,  and,  when  all  is  said,  it  is  difficult  to  decide 
between  the  two  families  as  to  their  relative  degrees  of  specialization. 
This  somewhat  drawn-out  discussion  leads  to  the  following  conclusions: 
(1)  the  progenitor  of  the  Hymenoptera  possessed  a  pair  of  larvapods  on 
each  of  the  first  ten  abdominal  segments  and  a  pair  of  segmented  subanal 
appendages  on  the  eleventh  segment;  (2)  the  progenitor  gave  rise  to  dis- 
tinct stocks  which  resulted  in  the  production  of  larvae  with  larvapods  in 
one  case  and  with  subanal  appendages  in  the  other;  (3)  the  Xyelidae 
represents  the  former  line  of  evolution  and  the  Pamphiliidae  the  latter; 
and  (4)  the  question  as  to  whether  the  Pamphiliidae  is  more  generalized 
than  the  Xyelidae  or  vice  versa  is  by  its  nature  unanswerable.  To  the 
above  conclusions  it  may  be  added  that  it  is  only  natural  and  reasonable  to 
consider  the  Tenthredinidae  as  representing  the  further  evolution  of  the 
primitive  stock  from  which  the  Xyelidae  had  evolved,  and  the  Cephidae, 
Xiphidriidae,  Siricidae,  and  Oryssidae,  in  turn,  as  evolving  from  the 
original  stock  which  gave  rise  to  the  Pamphiliidae. 

The  subanal  appendages  are  present  only  in  the  Pamphiliidae  and 
Cephidae.  In  the  former  they  are  rather  long,  setiform,  well  developed, 
distinctly  three-segmented;  in  the  latter  they  are  minute,  vestigial,  often 
fleshy,  papilla-like,  and  indistinctly  segmented.  Since  the  embryonic 
history  of  these  appendages  has  not  been  studied,  their  true  nature  is  not 
known.  There  is  little  doubt  but  that  they  are  true  appendages.  If  they 
represent  the  appendages  of  the  ultimate  segment,  as  has  been  suggested 
by  certain  writers,  and  correspond  to  the  so-called  style  of  generalized 
insects,  then  their  presence  is  an  indication  of  a  primitive  condition.  There 
is  hardly  any  question  as  to  the  common  origin  of  the  subanal  appendages 
in  the  Pamphiliidae  and  Cephidae,  and  if  these  structures  represent  what 
they  are  assumed  to  represent  these  two  families  must  have  a  close  affinity. 

The  ocellarae  are  present  in  the  Pamphiliidae,  Xyelidae,  Tenthredin- 
idae, and  Cephidae.  They  are  well  developed,  and  are  usually  accompanied 
by  well-defined  ocularia  in  the  first  three  families.  In  the  Cephidae  the 
ocellarae  are  vestigial  and  represented  by  localized  pigmented  granules, 
and  lack  ocularia.  It  is  significant  that  the  ocellarae  are  unmodified  in 
the  gall-makers  and  leaf-miners  of  the  family  Tenthredinidae,  except  in 
Phlebatrophia,  where  they  are  reduced  in  size  and  the  ocularia  indistinct. 
The  atrophy  of  the  ocellarae  is  undoubtedly  correlated  with  the  mining 
habit  of  the  larvae. 


445]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  127 

The  antennae  are  present  in  all  larvae  of  the  Tenthredinoidea.  Judg- 
ing from  the  condition  obtaining  in  generalized  insects,  it  is  reasonable  to 
consider  the  antennae  of  the  Pamphiliidae  as  representing  the  primitive 
ancestral  type.  They  are  long  and  setiform  in  this  family  and  consist  of 
seven  cylindrical  well-chitinized  segments.  The  Xyelidae  is  closely 
related  to  the  preceding  family  in  antennal  characters  altho  a  shortening 
of  the  length  has  taken  place.  In  the  Tenthredinidae  the  antennae  undergo 
much  modification  both  in  the  number  and  form  of  the  segments.  They 
may  be  conical,  limpet-shaped,  or  flattened,  and  the  number  of  segments 
varies  from  five  to  one.  The  antennae  of  the  Cephidae  resemble  those  of 
the  Xyelidae  and  some  of  the  Tenthredinidae  in  shape  and  number  of 
segments.  The  antennae  undergo  steady  reduction  in  size  and  number  of 
segments  in  the  three  remaining  families,  reaching  the  extreme  of  reduc- 
tion in  the  Oryssidae,  where  each  is  represented  by  a  button-like  swelling. 
The  trend  of  specialization  in  the  antennae  is  orthogenetic  so  far  as  the 
families  are  concerned  but  quite  diverse  in  the  subfamilies  of  the  Ten- 
thredinidae. 

The  mouth-parts,  which  include  the  mandibles,  maxillae  and  labium, 
afford  a  fertile  field  for  characters  which  are  of  interest  from  a  systematic 
point  of  view.  The  mandibles,  like  the  antennae,  are  the  most  persistent 
and  ever-present  structures  in  the  head  of  all  larvae  of  the  Tenthredinoidea. 
The  maxillary  and  labial  palpi  are  typically  four-and  three-segmented 
respectively.  The  change  is  in  the  reduction  in  number  and  size  of  the 
segments.  The  Cephidae  is  normal  in  this  respect  but  gradual  change 
takes  place  in  the  Xiphydriidae  and  Siricidae,  while  in  the  Oryssidae  the 
change  has  proceeded  so  far  as  to  completely  obliterate  the  maxillary  and 
labial  palpi.  The  palpi  of  Phlebatrophia  resemble  those  of  the  specialized 
families.  The  families  represent  different  stages  of  specialization,  and 
their  relative  systematic  position  can  be  indicated  by  the  degree  of  changes 
in  the  mouth-parts. 

The  suranal  process  which  is  located  on  the  meson  of  the  suranal 
lobe  or  the  tenth  urotergum  is  characteristic  of  the  larvae  of  the  Cephidae, 
Xiphydriidae,  and  Siricidae.  It  should  not  be  confused  with  the  caudal 
protuberances  of  certain  Tenthredinidae,  as  these  two  structures  are 
of  an  entirely  different  nature.  There  is  a  minute  hook-like  process  on  the 
caudo-meson  of  the  tenth  abdominal  tergum  of  the  Pamphiliidae.  It 
should  be  noted  that  in  certain  larvae  of  Pontania  and  Caulocampus  the 
caudal  portion  of  the  ultimate  tergum  is  produced  caudad  as  a  blunt  more 
or  less  strongly  chitinized  protuberance  which  undoubtedly  serves  the 
same  function  as  the  suranal  process  of  the  specialized  families.  These 
two  structural  modifications  of  the  caudal  end  of  the  body,  however,  are 
not  homologous  with  each  other.     The  suranal  process  is  undoubtedly 


128  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [446 

an  adaptive  structure  which  has  arisen  in  response  to  the  habit  of  the 
larvae  and  does  not  represent  the  true  appendages  of  the  segment,  to 
which  the  suranal  lobe  belongs.  For  this  reason  the  caudal  process  is  of 
less  significance  phylogenetically  than  the  subanal  appendages  of  the 
Pamphiliidae  and  Cephidae. 

The  metathoracic  spiracles  of  the  larvae  are  either  obsolete  or  vestigial 
in  the  majority  of  the  Tenthredinoidea.  The  larvae  of  the  Cephidae  and 
Siricidae  differ  from  all  others  in  that  the  metaspiracles  are  functional 
and  as  large  as  the  abdominal  spiracles.  It  is  important  to  ascertain  the 
original  condition  of  the  metaspiracles  in  these  families  because  upon  the 
interpretation  of  their  primitive  condition  depends  their  phylogenetic 
value  and  hence  the  relationship  between  these  two  families  and  also 
between  them  and  other  families.  It  is  considered  reasonable  to  assume 
that  the  progenitor  of  insects  and  hence  the  ancestor  of  the  Hymenoptera 
possessed  functional  spiracles  on  all  the  segments  of  the  body  including  the 
metathorax,  and  that  their  metaspiracles  must  have  been  as  large  as  the 
abdominal  spiracles.  The  closed  minute  functionless  metaspiracles  found 
in  the  Pamphiliidae,  Xyelidae,  and  others,  indicate  a  condition  of  atrophy 
rather  than  a  rudimentary  condition,  and  so  far  as  this  character  is  con- 
cerned the  Cephidae  and  Siricidae  represent  the  unmodified  primitive 
condition  and  some  sort  of  relation  between  these  two  families  must  be 
assumed.  But  on  the  basis  of  other  characters  it  is  not  conceivable  that 
these  two  families  evolved  one  from  the  other  in  a  linear  sequence,  apart 
from  and  independent  of  other  families;  they  must  have  descended  from 
a  common  stock  which  also  gave  rise  to  other  families  which  exhibit 
vestigial  metaspiracles.  If  this  is  true  there  must  have  taken  place  a 
series  of  dichotomies  starting  with  functional  metaspiracles,  one  line  of 
development  resulting  in  the  loss  of  this  primitive  character  and  the  other 
line  of  evolution  retaining  the  original  condition.  By  assuming  four  such 
successive  dichotomies  in  the  line  of  evolution,  the  origin  and  significance 
of  the  metaspiracles  of  the  Cephidae  and  Siricidae  can  be  reasonably 
explained.  At  each  of  the  four  successive  dichotomous  divisions  which 
produced  respectively  the  pamphiliid-like  progenitor  and  Xyelidae, 
Pamphiliidae  and  the  cephid-like  progenitor,  Cephidae  and  the  xiphydriid- 
like  progenitor,  and  Xiphydriidae  and  Siricidae,  one  line  of  descent  always 
carried  the  original  character  and  the  other  line  lost  it  until  this  peculiarity 
was  generally  sifted  out,  being  retained  unmodified  only  in  the  Cephidae 
and  Siricidae.  In  this  way  the  metaspiracles  are  here  considered  to  be 
the  direct  descendant  of  the  primitive  structures  which  remained  unmod- 
ified thruout  the  course  of  evolution  of  these  families.  The  two  families 
are  generalized  in  this  respect  indicating  a  close  genetic  relation. 


447] 


LARVAE  OF  THE  TENTHREDINOIDEA—YUASA 


129 


The  morphological  characters  discussed  are  summarized  in  the  following 
table: 

Comparison  of  Various  Structures  in  the  Families  o*  the  Tenthredinoidea 


Structure 

Pamphi- 
liidae 

Cephidae 

Xiphy- 
driidae 

Siricidae 

Oryssidae 

Xyelidae 

Tenth- 
redinidae 

Thoracic  legs 

5-seg- 
mented 

Fleshy 

Fleshy 

Fleshy 

Wanting 

5-seg- 
mented 

S-,  4-,  3- 

segmented 

Larvapods 

Wanting 

Wanting 

Wanting 

Wanting 

Wanting 

10  pairs 

6-8  pairs 

Subanal 

appendages 

Distinct, 
long 

Vestigial 

Wanting 

Wanting 

Wanting 

Wanting 

Wanting 

Ocellarae 

Distinct 

Vestigial 

Wanting 

Wanting 

Wanting 

Distinct 

Distinct 

Antennae 

7-seg- 

5-  and  4- 

3- seg- 

1-seg- 

1-seg- 

7- and  6- 

5-,  4-,  and  1- 

mented 

segmented 

mented 

mented 

mented 

segmented 

segmented 

Mouth-parts 

Typical 

Typical 

Modified 

Modified 

Vestigial 

Typical 

Typical,  rare- 
ly modified 

Suranal  process 

Wanting 

Distinct 

Distinct 

Distinct 

Wanting 

Wanting 

Wanting 

Meta  thoracic 

spiracles 

Vestigial 

Functional 

Vestigial 

Functional 

Vestigial 

Vestigial 

Vestigial 

The  Pamphiliidae,  with  its  long  seven-segmented  antennae,  setiform 
three-segmented  subanal  appendages,  setiform  five-segmented  thoracic 
legs,  well-developed  typical  mouth-parts,  together  with  the  absence  of 
larvapods,  is  unquestionably  one  of  the  most  generalized  families  of  the 
Tenthredinoidea.  This  family  differs  from  the  hypothetical  type  only 
in  the  absence  of  larvapods  and  reduced  metaspiracles. 

The  Xyelidae,  with  its  fairly  long  seven-and  six-segmented  antennae, 
five-segmented  thoracic  legs,  well-developed  typical  mouth-parts,  together 
with  the  presence  of  ten  pairs  of  larvapods  and  the  absence  of  subanal 
appendages,  is  undoubtedly  a  very  generalized  family,  quite  different 
from  the  preceding.  The  only  striking  difference  from  the  hypothetical 
type  is  the  absence  of  the  subanal  appendages  and  functional  metaspiracles. 

The  Tenthredinidae,  with  its  one-  to  five-segmented  antennae,  well- 
developed  thoracic  legs,  and  six  to  eight  pairs  of  larvapods,  together  with 
the  absence  of  the  subanal  appendages,  is  unquestionably  related  to  the 
Xyelidae,  and  if  it  has  not  been  evolved  directly  from  the  latter  the  two 
families  must  have  arisen  from  a  common  stock.  The  Tenthredinidae  is  a 
phylogenetic  complex  in  itself,  and  some  of  the  more  specialized  genera  are 
further  removed  from  the  more  generalized  genera,  biologically  as  well  as 
morphologically,  than  the  latter  are  from  the  Xyelidae  or  their  xyelid- 
like  ancestors. 

The  Cephidae,  with  its  segmented  antennae,  vestigial  subanal  append- 
ages, vestigial  thoracic  legs,  normal  mouth-parts,  absence  of  larvapods, 
presence  of  suranal  process,  vestigial  ocellarae,  and  large  functional 
metaspiracles,  is  considered  an  offshoot  of  the  ancestral  stem  from  which 


130  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [448 

the  Pamphiliidae  had  previously  evolved.  The  specialization  is  indicated 
by  the  vestigial  condition  of  the  ocellarae,  subanal  appendages,  and 
thoracic  legs,  on  the  one  hand,  and  the  development  of  suranal  processes 
on  the  other.  The  presence  of  the  functional  metaspiracles  is  of  phy- 
logenetic  importance.  So  far  as  the  head  characters  are  concerned,  this 
family  resembles  the  Tenthredinidae  to  a  limited  extent,  and  in  some  of 
the  generalized  genera  of  the  latter  the  thoracic  legs  and  the  caudal  portion 
of  the  tenth  abdominal  segment  undergo  some  modifications  which  in  a 
remote  sense  simulate  the  condition  in  the  Cephidae.  But  since  this 
family  differs  from  the  Tenthredinidae,  and  resembles  the  Pamphiliidae  in 
the  absence  of  larvapods  and  the  presence  of  subanal  appendages,  it  is 
considered  more  reasonable  to  ascribe  to  it  a  closer  relationship  to  the 
Pamphiliidae  than  to  the  Tenthredinidae. 

The  Xiphydriidae,  with  its  somewhat  modified  mouth-parts,  three- 
segmented  antennae,  fleshly  thoracic  legs,  suranal  process,  absence  of 
larvapods,  the  general  shape  of  the  body,  and  its  biology,  resembles  the 
Cephidae  but  differs  from  it  in  theabsence  of  subanal  appendages,  ocellarae, 
and  in  the  vestigial  functionless  metaspiracles.  The  absence  of  the  subanal 
appendages  may  point  to  one  of  the  two  possibilities  in  regard  to  the  origin 
of  the  Xiphydriidae.  This  family  might  have  evolved  from  the  cephid- 
like  ancester  but  have  lost  the  subanal  appendages  by  the  completion  of 
the  process  of  atrophy  which  had  already  reduced  the  original  distinctly- 
segmented  appendages  (similar  to  those  of  the  Pamphiliidae)  to  the 
vestigial  papilliform  appendages  of  the  Cephidae.  The  two  families 
under  consideration  might,  on  the  other  hand,  have  had  a  common  stem 
which  possessed  subanal  appendages,  ocellarae,  and  vestigial  metaspiracles. 
In  the  absence  of  positive  support  for  the  first  possibility,  it  is  more 
expedient  to  consider  the  second  possibility  as  nearer  to  the  true  rela- 
tionship of  the  two  families,  Xiphydriidae  and  Cephidae. 

The  Siricidae,  with  its  greatly  reduced  thoracic  legs  and  mouth-parts 
together  with  certain  other  characters,  is  considered  more  specialized 
than  the  Xiphydriidae.  The  presence  of  the  functional  metaspiracles 
and  its  genetic  significance  have  already  been  discussed.  For  the  same 
reason  which  suggests  a  common  origin  for  the  Cephidae  and  Xiphy- 
driidae, the  Siricidae  is  considered  to  have  arisen  from  a  common  stock 
which  gave  rise  also  to  the  Xiphydriidae.  In  the  degree  of  specialization 
by  reduction  as  well  as  by  addition,  this  family  outranks  the  Xiphydriidae. 

The  Oryssidae,  with  its  vestigial  mouth-parts,  absence  of  ocellarae, 
thoracic  and  abdominal  legs,  subanal  appendages,  suranal  process,  caudal 
protuberances,  and  functional  metaspiracles,  together  with  its  parasitic 
habit,  is  unquestionably  the  most  highly  specialized  family  of  the  Ten- 
thredinoidea.  Its  morphological  and  biological  characters  are  so  different 
from  other  families  that  it  is  not  easy  to  ascertain  the  systematic  position 


449]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  131 

of  the  family.  There  are,  however,  certain  considerations  which  suggest 
a  possible  relationship  between  this  family  and  the  Siricidae.  Morpho- 
logically the  oryssid  larvae  are  more  closely  related  to  the  apodous  boring 
larvae  of  the  Cephidae,  Xiphydriidae,  and  Siricidae  than  to  the  polypodous 
free-living  larvae  of  the  Xyelidae  and  Tenthredinidae.  The  siricid  larvae 
are  more  closely  related  to  those  of  the  Oryssidae  than  to  those  of  the 
Cephidae  and  Xiphydriidae.  The  parasitic  habit  also  suggests  a  closer  re- 
lation to  the  wood-boring  larvae  since  it  is  more  plausible  to  imagine  the 
possibility  of  a  wood-boring  larvae  becoming  parasitic  on  other  wood- 
boring  insect  larvae  under  some  unknown  but  not  entirely  inconceivable 
circumstances  than  to  imagine  the  development  of  a  parasitic  habit  de  novo 
in  free-living  leaf-feeders.  Since  the  oryssid  larvae  are  parasitic  on  the 
larvae  of  Buprestis  inhabiting  plants  which  are  also  infested  by  the  larvae 
of  the  Siricidae,  if  any  transformation  of  habit  of  the  larvae  has  taken 
place,  it  is  more  natural  to  expect  the  larvae  of  the  Siricidae  or  some 
siricid-like  insect  to  become  parasitic  than  any  other  larvae.  The  recent 
investigation  by  Baumberger  (1919)  on  the  role  of  microorganisms  in 
the  physiology  of  insect  nutrition  offers  a  valuable  suggestion  in  regard  to 
the  possibility  of  radical  changes  in  food  habits.  For  these  reasons  it  is 
considered  reasonable  to  ascribe  a  common  progenitor  to  the  Siricidae 
and  Oryssidae,  at  least  for  the  time  being.  It  may  be  added  that  it  is 
not  entirely  unreasonable  to  assume  an  independent  line  of  evolution 
for  the  Oryssidae  apart  from  all  other  Tenthredinoidea  and  consider 
this  family  as  having  no  close  relation  to  any  of  the  modern  families  of  the 
Tenthredinoidea.  In  that  case,  the  Oryssidae  must  have  arisen  from  the 
ancestral  stock  before  the  Pamphiliidae  and  Xyelidae  had  their  origin. 
There  is,  however,  no  clear  evidence  in  support  of  such  relation  and 
since  the  relation  is  reasonably  explained  by  associating  the  Oryssidae 
with  the  Siricidae,  the  former  is  considered  the  most  highly  specialized 
family  of  the  Tenthredinoidea  with  a  common  origin  with  the  ancestor  of 
the  Siricidae. 

The  conclusions  on  the  systematic  position  and  relationship  of  the 
different  families  of  the  Tenthredinoidea  based  exclusively  on  larval 
characters  and  derived  entirely  independent  of  the  opinions  of  the  spe- 
cialists who  have  paid  more  attention  to  the  adults  are  of  necessity  not 
the  final  words  on  the  subject.  The  true  significance  of  such  conclusions 
lies  in  their  complemental  and  collateral  value.  It  is  interesting  on  this 
account  to  compare  the  writer's  opinion  with  the  conclusions  of  the 
modern  authorities  on  this  group  of  the  Hymenoptera. 

The  relationship  suggested  here  supports  in  its  essential  points  the 
three  more  important  systems  of  classification  proposed  by  Konow  (1905), 
MacGillivray  (1906),  and  Rohwer  (1911).  MacGillivray  considered  the 
Xyelidae  the  most  primitive  because  of  the  venational  character  but 


132  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [450 

recognized  the  Pamphiliidae  as  the  most  generalized  from  his  study  (1913) 
of  the  immature  stages.  Had  he  placed  the  Pamphiliidae  before  the 
Xyelidae  and  the  Cephidae  before  the  Xiphydriidae  and  Siricidae,  his 
system  would  coincide  exactly  with  the  system  based  exclusively  on  the 
immature  stages.  Konow  and  Rohwer  both  associate  the  Cephidae 
with  the  Pamphiliidae  and  Xyelidae.  This  arrangement  is  partly  supported 
if  the  affinity  between  the  Pamphiliidae  and  Cephidae,  as  suggested  in 
this  study,  is  upheld.  The  genetic  continuity  of  the  Xyelidae  and  Ten- 
thredinidae  is  clearly  recognized  by  MacGillivray  (1913).  The  true 
systematic  position  of  the  Tenthredinidae  or  its  equivalent  is  difficult 
to  express  in  linear  arrangement.  The  important  point  to  be  noted  is  the 
fact  that  these  authors  and  also  Morice  (1919)  consider  the  Xyelidae  and 
Tenthredinidae  as  different  and  apart  from  the  other  families  of  the 
Tenthredinoidea.  The  Oryssidae  unquestionably  merits  at  least  separate 
family  rank.  In  the  absence  of  requisite  knowledge  of  the  larval  characters 
of  the  Hymenoptera  other  than  the  Tenthredinoidea,  it  is  not  expedient 
to  venture  any  opinion  on  the  suggestion  made  by  Rohwer  and  Cushman 
(1917)  to  establish  a  third  suborder,  Idiogastra,  for  the  reception  of  the 
Oryssidae.  Enslin  (1911)  differs  from  the  authors  already  mentioned 
not  only  in  his  arrangement  of  the  groups  in  a  descending  order  but  also  in 
treating  the  Xyelidae  and  Pamphiliidae  as  subfamilies  of  his  Tenthredini- 
dae, on  a  level  with  the  Cimbicini,  Lophrini,  and  others.  This  study  does 
not  support  his  arrangement.  Morice  (1919)  suggested  that  "the  Lydini 
(Pamphiliidae  Ensl.)  may  represent  a  primitive  group  of  Tenthredinidae 
which  had  branched  off  from  the  main  stock  before  it  had  developed 
certain  characters,"  such  as  abdominal  legs.  Handlirsch  (1908)  considered 
the  Siricidae  as  having  evolved  from  the  osculant  Juracic  group,  Pseudo- 
siricidae.  The  antiquity  of  the  Siricidae  is  accepted  by  Morice  who 
expresses  his  idea  of  the  relationship  of  the  families  of  the  Tenthredinoidea 
as  follows:  "We  may  suppose  that  the  Siricidae  are  the  earlier  group, 
but  whether  the  Tenthredinidae  and  Lydini  had  Siricid  ancestors,  or 
whether  the  Siricidae-f-Cephini-f-Oryssidae  and  Tenthredinidae+ Lydini 
are  respectively  earlier  and  later  branches  of  a  common  stock  are  questions 
which  must  be  left  unanswered." 


451]  LARVAE  OF  THE  TENTHREDINOIDEA—YVASA  133 


V.    SUMMARY 

The  larvae  of  the  Tenthredinoidea  have  proved  to  be  of  great  value  in 
affording  important  evidence  in  regard  to  the  probable  phylogenetic 
relationship  of  the  families  included  in  this  superfamily.  The  more 
significant  conclusions  reached  in  this  study  are  summarized  in  the  form 
of  a  synoptic  key  as  follows: 

FAMILIES  OF  TENTHREDINOIDEA 

Larvapods  present,  thoracic  legs  present,  well  developed,  distinctly  segmented. 

Larvapods  present  on  all  abdominal  segments Xyelidae 

Larvapods  never  present  on  1st  and  9th  abdominal  segments Tentkredinidae 

Larvapods  wanting,  thoracic  legs  present  or  wanting. 
Thoracic  legs  present. 
Thoracic  legs  and  subanal  appendages  well-developed  and  distinctly  segmented. 

Pamphiliidae. 
Thoracic  legs  vestigial,  indistinctly  segmented. 

Subanal  appendages  and  ocellarae  present Cephidae. 

Subanal  appendages  and  ocellarae  wanting. 
Metaspiracles  vestigial,  much  smaller  than  abdominal  spiracles. .  . Xiphydriidae. 

Metaspiracles  functional,  as  large  as  abdominal  spiracles Siricidae. 

Thoracic  legs  wanting Oryssidae. 

A  synopsis  such  as  the  foregoing  is  necessarily  inadequate  and  some- 
what misleading  in  indicating  the  affinities  of  the  families.  A  better  idea 
is  gained  by  means  of  the  customary  phylogenetic  tree,  altho  such  a 
scheme  also  has  its  limitations.  In  the  following  diagram  the  relation 
between  the  families  of  the  Tenthredinoidea  is  shown.  Here  the  relative 
vertical  positions  are  intended  to  represent  approximately  the  degree 
of  specialization;  and  the  continuous  lines,  the  affinities. 

The  larvae  of  the  Tenthredinoidea  are  thus  divisible  into  two  distinct 
groups.  The  first  group  includes  the  larvae  characterized  by  the  presence 
of  both  the  thoracic  and  abdominal  legs,  and  by  the  absence  of  the  subanal 
appendages  and  suranal  process,  and  is  represented  by  the  Xyelidae 
and  Tenthredinidae.  The  second  group  consists  of  the  five  families, 
Pamphiliidae,  Cephidae,  Xiphydriidae,  Siricidae,  and  Oryssidae,  and  is 
divisible  into  two  subgroups.  The  first  subgroup  contains  the  first  four 
families  and  is  characterized  by  the  absence  of  abdominal  legs,  by  the 


134 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[452 


presence  of  vestigial  clawless  thoracic  legs  in  the  last  three  families,  and 
by  the  presence  of  either  subanal  appendages  or  suranal  process  or  both. 
The  second  subgroup  contains  a  single  family,  Oryssidae,  which  is  charac- 
terized by  the  absence  of  both  thoracic  and  abdominal  legs,  suranal 


Highly 
Specialized 

Tenthredinidae 
(specialized)! 

Oryssidae 

Siricidae  / 
/  / 

Xiphydriidae  /  / 

Specialized 

Tenthredinidae 1 
(generalized) 1 

/  //          Oephidae 

Generalized 

Xyelidae     \l 

/  /     i'amphiliidae 

Primitive 


Pro- 

-Symphyta 

Fbylogenetic  tree  indicating  the  probable  affinities  of  various  families  of  the  Tenthredinoidea 


process,  subanal  appendages,  and  segmented  maxillary  and  labial  palpi. 
The  Xyelidae  and  Pamphiliidae  are  undoubtedly  the  most  primitive  of  the 
first  and  second  groups  respectively. 

The  Tenthredinoidea,  therefore,  is  considered  to  have  developed 
from  a  common  ancestral  stock  along  two  distinct  lines  of  evolution. 
The  first  line  of  development  led  to  the  evolution  of  the  Xyelidae  and 
Tenthredinidae  and  the  second  line  produced  the  Pamphiliidae,  Cephidae, 
Xiphydriidae,  Siricidae,  and  Oryssidae. 


453]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  135 


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140  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (458 

SWAMMERDAM,  J. 

1737.    Biblia  naturae,  etc.    Leydae. 
Swenk,  M.  H. 

1911.  A  new  sawfly  enemy  of  the  bull  pine  in  Nebraska.    24th  Ann.  Rept.  Neb.  Agr. 
Exp.  Sta.,  1911. 

Townsend,  H.  T. 

1894.    Notes  on  the  Tenthredinid  gall  of  Euura  orbitalis  on  Saliz  and  its  occupants. 
Jour.  N.  Y.  Ent.  Soc.,  2:102. 
Walden,  B.  H. 

1912.  A  new  sawfly  pest  of  the  blackberry,  Pomphttius  denkUus  MacGfllivray.    Rept. 
Conn.  Agr.  Exp.  Sta.,  1912,  236-240. 

Walsh,  B.  D. 

1866.    Imported  insects;  the  gooseberry  sawfly.    Pract.  Ent,  1:117-125. 
Webster,  F.  M. 

1900.    The  purslane  sawfly,  Schizocerus  zabriskei  Ashm.    Can.  Ent.,  32:51-54. 
Westwood,  J.  O. 

1840.    An  introduction  to  the  modern  classification  of  insects.   London. 
Young,  Chester. 

1898.  The  larvae  of  the  Tenthredina.    Baccalaureate  thesis,  Cornell  University. 

1899.  Descriptions  of  sawfly  larvae.    Can.  Ent.,  31:41-43. 
Yuasa,  H. 

1920.    The  anatomy  of  the  head  and  mouth-parts  of  Orthoptera  and  Euplexoptera.  Jour. 
Morph.,  33:251-307. 


459]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  141 


PLATE  I 


142  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (460 


EXPLANATION  OF  PLATE 
LARVAE  OF  TENTHREDINOIDEA 

Fig.  1— Pamphiliidac.    Pamphilius  sp.  Y-125. 

Fig.  2 — Cephidae.  Janus  integer. 

Fig.  3 — Xiphydrudae.    Xiphydria  sp. 

Fig.  4 — Siricidae.  Tremex  columba. 

Fig.  5— Oryssklae.         Oryssus  occidentalis 

(After  Rohwer  and  Cushman,  1917). 
au     anus 

msp   mesothoracic  spiracle 
sba     subanal  appendage 
sp*     abdominal  spiracle 
srp     suranal  process 
tig*     mesothoracic  leg 
tsp     me ta thoracic  spiracle 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


•  •        '0  m 


YUASA    LARVAE  OF  THE  TENTHREDINOIDEA   PLATE  I 


461]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  143 


PLATE  II 


144 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[462 


EXPLANATION  OF  PLATE 
LARVAE  OF  XYELIDAE  AND  TENTHREDINIDAE 


Fig.    6 — Xyelidae. 
Fig.    7 — Tenthredinidae. 
Fig.    8— Tenthredinidae. 
Fig.    9 — Tenthredinidae. 
Fig.  10 — Tenthredinidae. 


Megaxyela  major. 

Diprioninae.      Neodipriron  lecontei. 
Emphytus  apertus. 
Strongylogaster  anmtlosus. 
Dolerus  similis. 
anus 

mesothoracic  spiracle 
larvapod 

abdominal  spiracle 
mesothoracic  leg 
metathoracic  spiracle 


Emphytinae. 
Selandriinae. 
Dolerinae. 


msp 

Pig 
spi 
tig1 
tsp 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA     PLATE  II 


463]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  145 


PLATE  III 


146 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[464 


Fig.  11 — Phyllotominae. 
Fig.  12 — Phyllotominae. 
Fig.  13 — Tenthredininae. 
Fig.  14 — Cimbicinae. 
Fig.  15 — Hoplocampinae. 


EXPLANATION  OF  PLATE 

LARVAE  OF  TENTHREDINIDAE 

Caliroa  cerasi. 
Phlebatrophia  mathesoni. 
Tenthredo  sp. 

A  bia  in  flat  a. 
Hemichroa  americana. 


au  anus 

tnsp  mesothoracic  spiracle 

pig  larvapod 

spi  abdominal  spiracle 

tig2  mesothoracic  leg 

tsp  metathoracic  spiracle 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA   PLATE  III 


465]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  147 


PLATE  IV 


148 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


m 


Fig.  16 — Cladiinae. 
Fig.  17 — Nematinae. 
Fig.  18 — Nematinae. 
Fig.  19 — Blennocampinae. 
Fig.  20 — Blennocampinae. 


EXPLANATION  OF  PLATE 

LARVAE  OF  TENTHREDINIDAE 

Cladius  pectinicornis. 
Pkronidea  ventralis. 
Pkronidea  ribesi. 
Monophadnoides  rubi. 
Tomostethus  bardus. 


an  anus 

msp  mesothoracic  spiracle 

pig  larvapod 

spi  abdominal  spiracle 

srp  suranal  process 

tig1  mesothoracic  leg 

tsp  metathoracic  spiracle 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA    PLATE  IV 


4671  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  149 


PLATE  V 


150 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[468 


EXPLANATION  OF  PLATE 
LARVAE  OF  TENTHREDINTDAE 


Fig.  21 — Fenusinae. 

Kaliofenusa  ulmi. 

Fig.  22 — Scolioneurinae. 

Meiallus  rubi. 

Fig.  23 — Hylotominae. 

Hylotoma  sp. 

Fig.  24 — Schizocerinae. 

Schizocerus  zabriskei. 

Fig.  25 — Acordulecerinae. 

Acordulecera  sp. 

au      anus 

msp   mesothoracic  spiracle 

pig     larvapod 

scp     sucker-like  protuberance 

spi     abdominal  spiracle 

tig  *     mesothoracic  leg 

tsp     meta thoracic  spiracle 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDP:A      PLATE  V 


469]  LARVAE  OF  THE  TENTHREDINOIDEA—YAUSA  151 


PLATE  VI 


152 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


(470 


EXPLANATION  OF  PLATE 
CEPHALIC  ASPECT  OF  THE  HEAD 


Fig.  26 — Pompkttius  sp. 
Fig.  27 — Megaxyda  major. 
Fig.  28 — Neodiprion  lecontei. 
Fig.  29 — Abia  americana. 
Fig.  30 — Pteronidea  ribesi. 
Fig.  31 — Lygaeonematus  erichsoni. 
Fig.  32 — Endelomyia  aethiops. 


a 

antenna 

an 

antacoria 

or 

antennaria 

c 

dypeus 

cl 

clypealia 

els 

clypeo-labra)  suture 

crv 

sericos 

cs 

clypeal  suture 

ea 

epicranial  arm 

es 

epicranial  stem 

f 

front 

fes 

fronto-clypeal  suture 

gl 

galea 

hx 

hypopharynx 

inl 

line  of  invagination 

I 

labrum 

IP 

labial  palpus 

Is 

labral  setae 

Fig.  33 — Macremphytus  variatms. 
Fig.  34 — Kaliofenusa  ultni. 
Fig.  35 — MetaUus  rubi. 
Fig.  36 — Schizocerus  zabriskei. 
Fig.  37 — Phlebatrophia  mathesoni. 
Fig.  38 — Dolerus  similis. 


ma  muscular  attachment 

mb  mandibularia 

mi  mandible 

mds  mandibular  setae 

mp  maxillary  palpus 

mx  maxilla 

o  ocellara 

ou  ocularia 

pe  preclypeus 

pn  pretentorina 

po  postclypeus 

pr  precoila 

py  preartis 

v  vertex 

»/  vertical  furrow 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA    PLATE  VI 


471]  LARVAE  OF  THE  TENTHRED1N0IDEA—YUASA  153 


PLATE  VII 


154 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[472 


EXPLANATION  OF  PLATE 


VENTRAL  ASPECT  OF  THE  HEAD  AND  PROTHORAX 


Fig.  39 — PamphUus  sp. 

Fig.  40 — Megaxyda  major. 

Fig.  41 — Koliofenusa  ulmi. 

Fig.  42 — Dolerus  simttis. 

Fig.  43 — Neodiprion  lecontei. 

Fig.  44 — Macremphytus  varianus. 

a 

antenna 

an 

antacoria 

c 

clypeus 

cc 

cervacoria 

d 

clypealia 

ds 

clypeo-labral  suture 

en 

sericos 

cw 

tarsal  claw 

ex 

coxa 

ea 

epicranial  arm 

cc 

extensacuta 

es 

epicranial  stem 

f 

front 

fes 

fronto-clypeal  suture 

fm 

femur 

g 

gena 

gl 

galea 

hs 

hvpopharynx 

Fig.  45 — Xiphydria  sp. 

Fig.  46 — Trernex  columba. 

Fig.  47 — Lygeonematus  ericksoni. 

Fig.  48 — Enddomyia  adhiops. 

Fig.  49 — Met  alius  rubi. 

1 

labrum 

la 

lacinia 

les 

lateral  cervical  sclerite 

li 

labium 

IP 

labial  palpus 

mb 

mandibularia 

md 

mandible 

mp 

maxillary  palpus 

mx 

maxilla 

0 

ocellara 

Pin 

profurcellina 

pn 

pretentorina 

Pr 

precoila 

py 

preartis 

t 

tibia 

tr 

trochanter 

Ugl 

prothoracic  leg 

V 

vertex 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA      LARVAE  OF  THE  TENTHREDINOIDEA       PLATE  VII 


473]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  15$ 


PLATE  VIII 


156 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[474 


EXPLANATION  OF  PLATE 


VENTRAL  AND  DORSAL  ASPECTS  OF  HEAD  AND  PROTHORAX 


Fig.  50 — Janus  integer. 

Fig.  55 — Dolerus  similis. 

Fig.  51 — Schizocerus  zabriskei. 

Fig.  56 — Megaxyela  major. 

Fig.  52 — Phlebatropkia  mathesoni. 

Fig.  57 — Caliroa  cerasi. 

Fig.  53 — Caliroa  cerasi. 

Fig.  58 — Neodiprion  lecontei. 

Fig.  54 — Pamphilius  sp. 

Fig.  59 — Endelomyia  nethiops. 

a 

antenna 

la 

lacinia 

c 

clypeus 

Ic 

labicoria 

cc 

cervacoria 

li 

labium 

eg 

cervical  gland 

■     IP 

labial  palpus 

els 

clypeo-labral  suture 

m 

mentum 

erv 

sericos 

mb 

mandibularia 

em 

tarsal  claw 

md 

mandible 

ex 

coxa 

tnp 

maxillary  palpus 

M 

epicranial  arm 

msp 

mesothoracic  spiracle 

ec 

extensacuta 

mx 

maxilla 

es 

epicranial  stem 

0 

ocellara 

f 

front 

Pfn 

profurcellina 

fm 

femur 

pn 

pretentorina 

1 

gena 

i 

tibia 

gi 

galea 

^ 

prothoracic  leg 

hx 

hypopharynx 

m 

tarsus 

is 

intersegmental  line  (limit  of  somite)             v 

vertex 

I 

labrum 

*f 

vertical  furrow 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA       LARVAE  OF  THE  TENTHREDINOIDEA      PLATE  VIII 


475]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  157 


PLATE  IX 


1S8 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[476 


EXPLANATION  OF  PLATE 


DORSAL  AND  LATERAL  ASPECTS  OF  HEAD  AND  PROTHORAX 


Fig.  60 — Macremphytus  varianus. 
Fig.  61 — Monophadnoides  rubi. 
Fig.  62— Metallus  rubi. 
Fig.  63 — Patnphilius  sp. 
Fig.  64 — Megaxyela  major. 
Fig.  65 — Neodiprion  lecontei. 
Fig.  66 — Dolerus  similis. 


Fig.  67 — Macrcmphytus  varianus. 
Fig.  68 — Endelomyia  aeikiops. 
Fig.  69 — Caliroa  cerasi. 
Fig.  70 — Pteronidea  ribesi. 
Fig.  71 — Lygeonematus  ericksoni. 
Fig.  72 — Abia  americana. 


a 

antenna 

let 

lateral  cervical  sderite 

c 

clypeus 

li 

labium 

cc 

cervacoria 

IP 

labial  palpus 

eg 

cervical  gland 

mb 

mandibularia 

cw 

tarsal  claw 

md 

mandible 

ex 

coxa 

rnp 

maxillary  palpus 

ea 

epicranial  arm 

msp 

mesothoracic  spiracle 

ec 

extensacuta 

mx 

maxilla 

es 

epicranial  stem 

0 

ocellara 

f 

front 

Pr 

precoila 

fm 

femur 

py 

preartis 

t 

gena 

t 

tibia 

kx 

hypopharynx 

tr 

trochanter 

it 

intersegmental  line  (limit  of  somite) 

V 

vertex 

I 

labium 

4 

vertical  furrow 

la 

lacinia 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA    PLATE  IX 


477|  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  159 


PLATE  X 


160 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


1478 


EXPLANATION  OF  PLATE 
LATERAL  AND  VENTRAL  ASPECTS  OF  THIRD  ABDOMINAL  SEGMENT 


Fig.  73 — Pamphilius  sp. 
Fig.  74 — Endelomyia  atthiops. 
Fig.  75 — Dolerus  similis. 
Fig.  76 — Megaxyela  major. 
Fig.  77 — Neodiprion  lecontei. 
Fig.  78 — Macremphytus  varianus. 
Fig.  79 — Caliroa  cerasi. 
Fig.  80 — Pamphilius  sp. 


Fig.  81 — Dolerus  similis. 
Fig.  82 — Neodiprion  lecontei. 
Fig.  83 — Endelomyia  aethiops. 
Fig.  84 — Megaxyela  major. 
Fig.  85 — Caliroa  cerasi. 
Fig.  86 — Kaliofenusa  ulmi. 
Fig.  87 — Metallus  rubi. 
Fig.  88 — Macremphytus  varianus. 


al-al    annulets  1,  2,  3,  4,  5,  6,  7. 

ch  chitinized  area. 

cor  intersegmental  coria 

pig  larvapod 

sdl  surpedal  lobe  or  area 

spi  abdominal  spiracle 

ssl  subspiracular  lobe  or  area 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA 


LARVAE  OF  THE  TENTHREDINOIDEA     PLATE  X 


479]  LARVAE  OF  THE  TENTH  REDINOIDEA—YU ASA  161 


PLATE  XI 


162 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[480 


EXPLANATION  OF  PLATE 
LATERAL  AND  VENTRAL  ASPECTS  OF  CAUDAL  ABDOMINAL  SEGMENTS 


Fig.  89 — Megaxyda  major. 

Fig.  90 — Megaxyda  major. 

Fig.  91 — Pamphilius  sp. 

Fig.  92 — Macremphytus  varianus. 

Fig.  93 — Macremphytus  varianus. 

Fig.  94 — Caliroa  cerasi. 

Fig.  95 — Pamphilius  sp. 

Fig.  96 — Dolerus  similis. 

Fig.  97 — Caliroa  cerasi. 


Fig.    98 — Endelomyia  atthiops. 

Fig.    99 — MetaUus  rubi. 

Fig.  100 — Neodiprion  lecontei. 

Fig.  101 — Neodiprion  lecontei. 

Fig.  102 — Dolerus  similis. 

Fig.  103— M etallus  rubi. 

Fig.  I04r—Phlebatrophia  mathesoni. 
Ventral  aspect  of  third  ab- 
dominal segment. 


au 

anus 

al 

annulet  1 

a2 

annulet  2 

o6 

annulet  6 

ck 

chitinized  area 

PH 

larvapod 

sba 

subanal  appendage 

sbl 

subanal  lobe 

sdl 

surpedal  lobe  or  area 

spi 

abdominal  spiracle 

srl 

suranal  lobe 

ssl 

subspiracular  lobe  or  area 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA  LARVAE  OF  THE  TENTHREDINOIDEA    PLATE  XI 


481]  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  163 


PLATE  XII 


164 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


(482 


EXPLANATION  OF  PLATE 
CAUDAL  ASPECT  OF  HEAD,  ABDOMEN,  ABDOMINAL  APPENDAGES 


Fig.  105 — Kaliofenusa  ulmi.    Ventral  Fig. 

aspect  of  caudal  abdominal  segment. 

Fig.  106— Phkbatrophia  mathesoni.  Fig. 

Fig.  107— Xiphydria  sp. 

Fig.  108 — Cephas  Pygmaeus.  Fig. 

Fig.  109 — Adirus  trimaculatus. 

Fig.  110 — Xiphydria  sp.  Fig. 

Fig.  Ill — Hartigia  cressoni. 

Fig.  112 — Janus  integer.  Fig. 

Fig.  113 — Tremex  columba. 

Fig.  114 — Cephas  pygmaeus.    Caudal  end         Fig. 
of  the  abdomen  enlarged. 

Fig.  115 — Adirus  trimaculatus.  Fig. 

Fig.  116 — Adirus  trimaculatus.    Subanal  ap- 
pendage enlarged.  Fig. 

Fig.  117 — Hartigia  cressoni.    Subanal 

appendage  enlarged.  Fig. 

Fig.  118 — Janus  sp.    Subanal  appendage 

enlarged.  Fig. 

Fig.  119 — Cephus  Pygmaeus.   Subanal 
appendage  enlarged. 


120 — Tremex  columba.   Lateral  aspect  of 

suranal  process  enlarged. 

121 — Janus  integer.     Lateral  aspect  of 

suranal  process  enlarged. 

122 — Tremex  columba.    Dorsal  aspect  of 

suranal  process  enlarged. 

123 — Janus  integer.     Dorsal  aspect  of 

suranal  process  enlarged. 

124 — Pteronidea  ribesi.    Ventral    aspect 

of  third  abdominal  segment. 

125 — Pteronidea  ribesi     Lateral    aspect 

of  caudal  end  of  abdomen. 

126 — Pteronidea  ribesi.     Lateral  aspect 

of  caudal  end  of  abdomen. 

127 — Pteronidea  ribesi.    Dorsal  aspect  of 

caudal  end  of  abdomen. 

128 — Abia  americana.    Caudal  aspect  of 

the  head. 

129 — Neodiprion  lecontei.      Musculature 

of  third   abdominal  segment,     semidia- 

grammatic.    Annulets  numbered. 


au     anus 


cc 
ch 
cht 


cervacona 
chit inized  area 
chitinized  tubercle 


cor  cona 

ct  corpotentorium 

e s  epicranial  stem 

li  labium 

lp  labial  palpus 

1st  lateral  area  of  suranal  lobe 

nib  mandicoria 

mc  maxacoria 

mn  metatentorina 

tnp  maxillary  palpus 

ml  metatentorium 

mx  maxilla 


my 

maxillaria 

od 

odontoidea 

of 

occipital  foramen 

OS 

occipital  suture 

pa 

postgena 

Pgr 

postgenal  ridge 

PI 

paracoila 

Pig 

larvapod 

pa 

postcoila 

pa 

postgena 

sba 

subanal  appendage 

sbl 

subanal  lobe 

sU 

sublateral  lobe 

spi 

abdominal  spiracle 

srp 

suranal  process 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


129 


127 


YUASA       LARVAE  OF  THE  TENTHREDINOIDEA      PLATE  XII 


483|  LARVAE  OF  THE  TENTHREDINOIDEA—YUASA  165 


PLATE  XIII 


166  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [494 


EXPLANATION  OF  PLATE 

ANTENNAE,  LEGS,  SILK-GLANDS 

Fig.  130 — Patnphilius  sp.    Metathoracic  leg. 

Fig.  131 — Megaxyda  major.    Metathoracic  leg. 

Fig.  132 — Macremphytus  varianus.    Metathoracic  leg. 

Fig.  133 — Pteronidea  ribesi.    Mesothoracic  leg. 

Fig.  134 — Neodiprion  lecontei.    Metathoracic  leg. 

Fig.  135 — Dolerus  sitnilis.    Metathoracic  leg. 

Fig.  136 — Phlebatrophia  mathesoni.    Metathoracic  leg. 

Fig.  137 — Metallus  rubi.    Metathoracic  leg. 

Fig.  138 — Pteronidea  ribesi.    Mesothoracic  leg.    Dorsal  aspect. 

Fig.  139 — Sckizocerus  zabriskei.    Metathoracic  leg. 

Fig.  140 — Kaliofenusa  ulmi.    Metathoracic  leg. 

Fig.  141 — Caliroa  cerasi.    Metathoracic  leg. 

Fig.  142 — Endelomyia  aethiops.    Metathoracic  leg. 

Fig.  143 — Megaxyela  major.    Antena. 

Fig.  144 — Adirus  Irimaculatus.    Antenna. 

Fig.  145 — Sckizocerus  zabriskei.    Antenna. 

Fig.  146 — Cephus  pygmaeus.    Antenna. 

Fig.  147 — Metallus  rubi.  Antenna. 

Fig.  148 — Tremex  columba.    Antenna. 

Fig.  149 — Kaliofenusa  ulmi.    Antenna. 

Fig.  150 — Phlebatrophia  mathesoni.    Antenna. 

Fig.  151 — Janus  integer.    Antenna. 

Fig.  152 — Hartigia  cressoni.    Antenna. 

Fig.  153 — Thrinaximpressatus.    Antenna. 

Fig.  154 — Pteronidea  ribesi.    Antenna. 

Fig.  155 — Tremex  columba.    Mesothoracic  spiracle. 

Fig.  156 — Abia  americana.    Silk-glands. 

Fig.  157 — Abia  americana.    Labium,  hypopharynx,  and  portion  of  silk-glands,  enlarged. 

Fig.  158 — Abia  americana.    Lateral  aspect  of  cephalic  portion  of  silk-glands. 

Fig.  159 — Abia  americana.   Dorsal  view  of  silk-press,  hypopharynx  removed. 

Fig.  160 — Abia  americana.    Cephalic  view  of  labium  and  hypopharynx. 


al-a6  antennal  segments  1,  2, 

3,  4,  5,  and  6 

an      antacoria 

li 

labium 

crv     cericos 

IP 

labial  palpus 

cw      tarsal  claw 

M 

arrow  pointing  mesad 

ex      coxa 

sd 

duct  of  silk-glands 

D       arrow  pointing  dorsad 

s& 

cells  of  silk-gland 

fm      femur 

sgd 

small  duct  of  silk-glands 

fp      femoral  process 

slpr 

silk-press 

k*      hypopharynx 

ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


YUASA       LARVAE  OF  THE  TENTHREDINOIDEA      PLATE  XIII 


4853  LARVAE  OF  THE  TENTHREDINOWEA—YUASA  167 


PLATE  XIV 


168  ILLINOIS  BIOLOGICAL  MONOGRAPHS  \486 


EXPLANATION  OF  PLATE 

Chart  representing  graphically  the  relationship  of  various  taxonomic  units  or  groups 
according  to  the  more  important  modern  systems  of  classification  of  the  Tenthredinoidea  as 
proposed  by  Konow  (1905),  MacGillivray  (1906),  and  Rohwer  (1911-1918). 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


VOLUME  VII 


MORF.  IMPORTAHT  MODERN    SYSTEMS  OF  CLASSIPICAnOHOFIHKTRmHKEPinOIDEi 


KONOW 
1903 


MACGILLIVRAY 

1906 


ROHWER. 

HJM  ~-'l  8 


CHALASTOGASTKA        TENTHREDINOIDEA        CMALASTOGASTRA 


I  LYD1DAE 
Lydioi 

Me<j*»lodootides 

Lydides 
Ceprvini 
Xyelini 
BlastlcotomiiH 
ttSIRICIDAE 
Xiptydnni 
Sirictoi 

Si'Hcidcs 

lie  inecides 
Oryssioi 

*TENTHREDMtDAt 

Cimbicini 

Cimbicides 

Abi  id^s 

9yzy5JO!vid«s 
Anjini 

Abides 

5c+»izocerid*s 
LophyHni 

Lobocerotid 

rHer/^optorides, 

VkrrrfXAes 

LofhyHdes 
TentHredinini 

fteravtide? 

HoplOCIMHp' 

5)cnnocj\mpi 
Selandriade? 
Dolerides 
TVntKredmtfS 


fi 


IXYEUDAE  „ 

_  PAMPHILIIDAE 

m  DLASTICOTDHIDAE 

\KTEMTHRED)HIDAE 

Dipriooinae  [M 

Erofhjdioa* 

Selaodriinae 

Dolerin&c 

Pbyllotorm'rwc 
'  /Lycaotinae 
r  JTenlhrsdlnln* 

ICirobicinae 

IHeplocampinAf 
DioeMrinae 
floooctenina*  • 
Claditnae 
NemaHiMw 
&|e  nnoCa  ropi  n  ap  \ 

Fenusinae 

Scolioneill-inat'. 

Hylofofninai 
Sckix««xrina« 

ncali  inaf 

L>b«cerin»e 
Acorduleccrinae^ 

Pt€ry3i>fl>orioaev 

^Penjinaff 

,V.  XIPHYDRJIDA1 
W.SIRjaDAE 

Siricinatf 
1Wmecin»f 

VHMEGALODOIITIDAE 

YICEPHIDAE 

IX.ORVSSIDAE 


MEGALODONTOIDEA  I 
flEGALOOOHTIDAE. 

Meq^Jo.tontiixvp 
Paatpbiliirtae 

XYEUBAE 
CEPHIDAE 

ORYSSOipEA-ipiO^ji 


SIRECOI 

XIPHYDRIIDAE 
XipWdriinac 
Dcrecystinae 

SIRECIDAE 
5irecir»a? 

Sirccioi 
_.  Ktr\  I  ni 

TENTHREDINOIDEA 
CIMBECIDAE 
Cimbecinae 
dmbecini 

PK  e  "At  o  pc  i^in  i 
Z&r&rinae 

Rtru<i«cla«*IUriini 

ZAtA<?ini 

PERREYIIPAE 

Prrt  ryiinAP 
Pbi|oii>As|i>)iri>v.' 

ARGIDAE 

\BUSTICOTOM»DAE 

1THREDIMIDAE 
1  Pfpriooioae  (»«m»; 
AllantipAc 

TtXAonini 

Er-iocampini 

A|la»rrHr>i 

Dolerinatf 

Tcntbrcd  ininae 
(Vrincurini 
Trnthrvdlnini 

Mrssin&c 
FfcyUatotnirti 

.  rtossini 

Ath»liiru\c 
Enpt-ii"*^ 

Emu  iini 
L   Lyi  Aotini 

fMennoc»mpini 
PKymatocvi  inAf 
6VI  Aiutt-iinae 

Selandriini 

Struts  yl<*jstern»i 

l.vliinac 
N«rnAtinA*' 

Of  Jialini  .    .  ,  _  _, 

Hemict*romt  (i«»ia) 

'PTERYGOPHOKI DAE 


\ 


Ptery^orhorh 
Acorduleceri 

Ph  yl&<- t<->pK«giri«<> 


Acordulecerin&eiz 


turiinac  (2, 

PERGIDAE 
'LOBOCERIDAE 


YUASA       LARVAE  OF  THE  TENTHREDINOIDEA     PLATE  XIV 


487] 


LARVAE  OF  THE  TENTHREDINOIDEA—YUASA 


169 


INDEX 


Page 

abbotti 47 

abbreviates 110 

abdominalis 113 

Abia 65 

Abia,  species  of 66 

abietis 47 

abdomen 25 

acericaulis 69 

Acordulecera 103,  104 

Acordulecera,  species  of 103 

Acordulecerinae 44 

Acordulecerinae,  subfamily 103 

Adirus 109,  110 

aethiops 58 

albifrons 55 

americana 65,  66 

Amauronematus 76,  84 

Amauronematus,  species  of 84 

annulosus 53 

antennae 19,  127 

appendiculatus 77 

apricus 55 

arthrostyli 29 

attenuata 114 

aviingrata 41 

azaleae 84 

bardus 93 

basalis 113 

bethunei 99 

bilineata 62 

biviltata 79 

Blasticotoma 42 

Blasticotomidae,  family 42 

Blennocampa 92,  93 

Blennocampinae 43,  44 

Blennocampinae,  genera  of 92 

Blennocampinae,  subfamily 91 

borers 38 

Caliroa 58 

Caliroa,  species  of 59 

caudal  protuberances 27 

Caulocatnpus 67,  68, 69 


Page 

Cephaleia 106 

Cephidae 129 

Cephidae,  family 108 

Cephidae,  genera  of 109 

Cephus 109,  111 

Cephas,  species  of Ill 

cerasi 59 

cervacoria 22 

chloreus 83 

Cimbex 65 

Cimbicinae 44 

Cimbicinae,  genera  of 65 

Cimbicinae,  subfamily 64 

cinctus 109,  111 

Cladius 71,  74 

Cladiinae 44 

Cladiinae,  genera  of 71 

Cladiinae,  subfamily 70 

clypeus 17 

columba 116 

cornelli 86 

corpotentorium 19 

cressoni 112 

Croesus 76, 83 

demissa 89 

dentatus 107 

derosa 90 

despecta 69 

devincta 89 

Dimorphopteryx 51 

Dineura 69 

Dineurinae,  subfamily 69 

Diphadnus 75,  76, 77 

Diprion 46,  49 

Diprioninae 43 

Diprioninae,  subfamily 45 

dohrini 97 

Dolerus 55 

Dolerus,  species  of 56 

Dolerinae 43 

Dolerinae,  subfamily 54 

dorsalis 104 


170 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[488 


Page 

Dorytheus 55 

dyari 67 

ej&eta 87 

efflusa 87 

emeriia 87 

Emphytus 51 

Emphytinae 43,  44 

Emphytinae,  genera  of 50 

Emphytinae,  subfamily 49 

Empria 50 

Endelomyia 58 

epicranial  suture 15 

epinota 63 

EpUaxonus 50 

equina 88 

erichsoni 81 

Eriocampa 51 

erudiia 87 

Erythraspides 92,  94 

erythrogastra 86 

evanida 87 

fasciata 106 

Fenusa 97 

Fenusinae 45 

Fenusinae,  genera  of 96 

Fenusinae,  subfamily 96 

ferruginea 42 

flicta 63 

filiceti 42 

fistula 63 

flavipes 54 

formulae  of  segmented  appendages —  34 

free  leaf-feeders 37 

front 17 

fuivicrus 87 

fumipennis 95 

gall-makers 88 

genae 16 

glands 33 

glandubae 33 

gregarious 80 

Hartigia 110,  112 

head 14 

Hemichroa 67 

Hemitaxonus 50 

Hoplocampinae 44, 45 

Hoplocampinae,  genera  of 67 

Hoplocampinae,  subfamily 66 

kyalina 89 

Hylotoma 100,  101 


Page 

Hylotoma,  species  of 100 

Hylotominae 45 

Hylotominae,  subfamily 99 

Hypergyricus 92,  94,  95 

Hypergyricus,  species  of 94 

impressatus 53 

inanitus 105 

inconspicua 107 

inflata 66 

integer 110 

Isodictium 92,  95 

Janus 109,  110 

Janus,  species  of 110 

Kaliofenusa 97 

Konowia 113 

labium 21 

labrum 17 

laricis 68 

larvapods 29,  123 

latitarsus 83 

leaf-folder 89 

leaf-miners 37 

lecontei 47 

lineata 64 

lombardae 87 

longicollis 113 

luteotergum 84 

Lygaeonematus 75,  81 

macleayi 101 

M  acremphytus 51 

Macrophya 61,  62 

Macrophya,  species  of 63 

M  acgillivrayella 67 

Macroxyela 42 

major 41 

mandibles 20 

mandibularia 18 

Marlattia 67, 68 

mathesoni 60 

maxillae 21 

maxillariae 18 

Megalodontes 116 

Megalodontidae,  family 116 

Megaxyela 41 

mendica 88 

MetaUus 98 

Metallus,  species  of 99 

metamerism 30 

metatentoria 19 

metathoracic  spiracles 128 


LARVAE  OF  THE  TENTHREDINOIDEA—YUASA 


171 


Page 

Micronematus 75,  79,  100 

minor 42 

minutus 55 

modeslius 73 

Monoctenus 46, 48 

Monophadnoides 92,  95 

Monophadnus 92, 94 

Monosoma 51 

Monostegia 51 

mouth-parts 20,  127 

mulUcinctus 93 

murtfeldtiae 78 

musta 104 

Nematus 75,  82 

Nematus,  species  of 83 

Nematinae 44 

Nematinae,  genera  of 75 

Nematinae,  subfamily 74 

Neodiprion 46,  47,  48 

Neodiprion,  species  of 47 

Neopus 61, 62 

nest-builders 38 

Neurotoma 106,  107 

nubilipennis 94 

obsolete 59 

occidentalis 118 

occipital  foramen 18 

occiput 18 

ocellarae 126 

ocreatus 105,  108 

ocularia 16 

Odontoidea 19 

Odontophyes 41 

odoratus 86 

Oryssidae 130 

Oryssus 118 

Oryssidae,  family 117 

Pachynematus 76,  81 

Pachynematus,  species  of 82 

paehdus 72 

pattiolatus 73 

pamphiliid 105 

Pamphiliidae 129 

Pamphiliidae,  family 104 

Pamphiliidae,  species  of 105 

Pamphilius 105,  107,  108 

parasites 38 

paracoila 19 

Parataxonus 50 

parvulus 69 


Page 

patchiae 72 

pectinicomis 74 

Periclista 92 

Phlebatrophia 60 

Phlebatrophini 57 

Phlebatrophini,  tribe 59 

Phrontosoma 51 

Phyllotominae 44, 45 

Phyllotomini 57 

Phyllotomini,  genera  of 58 

Phyllotominae,  subfamily 57 

politus 54 

pomum 89 

Pontania 75,  76,  88,  98 

Pontania,  species  of 88 

postcoila 18 

precoila 18 

postpedes 29 

pretentoria 19 

prepharynx 22 

Priophorus 71,  73,  74 

Priophorus,  speciesof 73 

Pristiphora 75, 77, 78 

Pristiphora,  speciesof 77 

prolegs. 29, 30 

prolongata 113 

postgenae 18 

provancheri 113 

Pseudodineura 69 

Pteronidea 75, 76, 85, 86 

Pteronidea,  species  of 85 

pulatus 53 

ptdchella 64 

pygmaeae 94,  109,  112 

quercus-alba 59 

quercus-coccinea 59 

14-punctatus 62 

repertus 82 

ribesi 85, 87 

rubi 95,99 

scapularis 101 

Schizocerinae 45 

Schizocerinae,  subfamily 101 

Schizocerus 102 

Scolioneurinae 45 

Scolioneurinae,  subfamily 98 

Selandria 52, 54 

Selandriinae 43,  44 

Selandriinae,  genera  of 52 

Selandriinae,  subfamily 51 


172 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[490 


Page 

scmilutea 61 

setae 32 

simile 49 

similis 55, 56 

Siricidae 130 

Siricidae,  family 114 

spiracles 32 

spiraeae 93, 94 

spissicornis 116 

Strongylogasler 52, 53 

Strongylogaster,  species  of 53 

Strongylogastroidea 51 

subalbatus 82 

subanal  appendages 28, 126 

suranal  lobe 26, 27 

suranal  process 27, 127 

sychophanta 79 

Syntexis 110 

tabidus Ill 

tacitus 54 

Taxonus 51 

Tenthredinidae 129 

Tenthredinidae,  family 42 

Tenthredinidae,  subfamilies  of 43 

Tenthredininae 44 

Tenthredininae,  genera  of 61 

Tenthredininae,  subfamily 60 

Ten  three!  inoidea,  families  of 38, 133 

Tenthredinoidea,  superfamiry 37 

Tenthredo 61, 62 

Tenthredopsis 61 

tenth  urosternum 27 


Page 

tenth  urotergum 26 

tentorium 19 

thoracica 85 

thoracic  legs 23, 122 

thorax 23 

Thrinax 52 

Thrinax,  species  of 53 

tibiator 63 

Tomostethus 92, 93 

tormae 18 

Tracheitis 109,  111 

Tretnex 115, 116 

Trichiocampus 71, 73 

Trichiocampus,  species  of 72 

Trichiosoma 65 

trilineala 88 

trimaculatus 110 

trunk 22 

ulmi 97 

unicolor 48 

Unitaxonus 51 

ventralis 85 

vertex 16 

vescus 85 

virendus 84 

Xiphydria 113 

Xiphydriidae 130 

Xiphydriidae,  family 112 

Xyela 42 

Xyelidae 129 

Xyelidae,  family 39 

zabriskiei 102 


UNIVERSITY  OF  ILLINOIS-URBANA 
S70.SILL  C004 

ILLINOIS  BIOLOGICAL  MONOGRAPHS  URBANA 
7  1922 


3  0112  017753531 


